Bankers in PE just can't deal with ambiguity/out of the box tasks

This does make sense, I just do wonder why bankers continue to be the preferred profile (at least that is what it seems to be like in the London market)

Broadly share this POV - obviously there are exceptions, can have some thoughtful and fluent ex-bankers, but overall they don't deal with unstructured or ambiguous tasks as well (at least out of the gates). That said, ex-consultants can take a frustratingly long time to come up the curve on modeling and financial intuition, which is incredibly deleveraging for teams (can't staff them on anything but GLG calls at that point). My broad brushstrokes view is bankers are generally higher floor but also lower ceiling, and consultants are lower floor but higher ceiling. 

"I was always told how more sharp bankers are and more naturally suited to PE investing seats and especially this forum propagates this over and over (by bankers themselves) but I was surprised how there is often a complete lack of them to deal with more "ambigous" tasks." 

Please work on your grammar and diction. This was painful to read.

Hi OP - good post, and I agree with you that many junior bankers struggle with this as they progress in their career (myself included). There have been some good responses above that already cover off some of what I was going to say, but I think the reasons for this are as follows:

1. The junior banking experience - as an analyst/associate, for the most part you are told to "simply follow orders" - and frankly you don't have much time to do much else! Your MD/VP says you need to do another turn of the deck incorporating various comments, or the model needs updating etc - and you do it. And querying whether the work is strategically necessary (or even thinking about it) early in your career is not a smart move. E.g. you probably know that the 15th turn of this deck/model is unnecessary based on what the client said earlier on the call - but your MD asks for it, so you work on it till 3am. So independent thinking is very much discouraged.
2. Following on from the above, the one area you often are allowed to "take charge" and be "creative" is with the model - so that becomes your creativity outlet at work (at least it did for me!) Of course there were templates etc to follow and my VP/Associate had comments/preferences, but the model mechanics and the nitty gritty stuff is mostly completely up to the analyst. I realize this sounds a bit sad even saying it/writing it out loud, but honestly for me that was how I felt as a junior in IB. So modelling became my prized expert skill above everything else.
3. IB is a competitive place where everybody wants to be the smartest guy in the room. As a junior you're taught that being a model wizard makes you a rockstar (just read various threads here on WSO). And to a big extent that's true, as arguably anybody can update a slide deck etc. The danger here though is that juniors are taught to see "soft skills"  (which can help you think strategically later on) as irrelevant. So you go from thinking qualitative skills are basically useless as an analyst/associate, to being told they're suddenly vital in PE or at VP-level.

4. Covid/wfh has made this worse in my view. Yes wfh has lots of benefits, but as a junior in IB I'm really glad I was in-office so that I could overhear conversations, turn around to ask someone a question, or have my associate grab me and take me into the MD's office to chat about something. You really do learn a lot that way by osmosis. Whereas wfh as a junior you're basically just process-driven and doing task after task - yes you may be invited on to calls about the deal/with your MD so that you know what's going on, but often that won't happen. E.g. if your VP wants to chat to your MD, wfh he would probably just call him direct and so you won't be in the loop. If you're sat next to him there's a good chance he'll bring you with him since it's zero extra effort (versus setting up a teams call unnecessarily for a 5 min chat with the MD). That's my view anyway

   5. Banking culture - as someone pointed out above, consultants seem to have either more ability to push back or just less tolerance for doing 3am requests etc. So early on you are able to think about "what value does this really add, why am I doing this?" - whereas in banking your MD says jump and you ask how high. So that makes it harder as well.

   It's worth noting that it isn't just bankers who struggle with this step-change once they reach mid-level positions - lawyers also find it difficult too, e.g. you can be a rockstar lawyer racking up crazy billables, but if you're just only good at doing tasks and don't have a strategic understanding of why clients are doing certain transactions etc, you'll struggle to make partner.

Both bankers and consultants have their share of competent folks as well as idiots - I think OP is being a little charitable on the consultant side of the ledger.  At least in banking the math is expected to tie.  So much of consulting is fluffy PowerPoint bullshit to justify a decision that has already been made or draw some obvious conclusion (speaking as someone from banking in PE who has managed several consultant engagements).  And the structured, silly way a lot of consultants speak (e.g., Pete Buttigieg) is so obnoxious.  I can see how the slightly more well-rounded skillset of consultants can be useful at upper levels and the smart ones can be just as effective as finance guys but they'll have a hard time competing with bankers at the associate grind.  The tricky part about PE is if you aren't comfortable with all the modeling and financial analysis (which most consultants aren't) you'll have a hard time ever progressing beyond that because all of your time will be consumed by figuring it out, checking models, etc. instead of doing it correctly fast allowing you to pick your head up and develop higher order managerial skills and think about the broader thesis and process.  Obviously, a small number of consultants do this and become excellent PE investors, but I think it's pretty straightforward why most PE firms hire most associates from banking - the skillset directly translates, bankers on balance have a higher "pain tolerance" and most associates won't be with the firm more than 2-3 years anyway so in some sense you just want robots who can do the analysis with the least amount of hand-holding.

Speaking as an ex-MBB consultant, I think what OP notices is selection bias.

In banking, you’re told where to focus, what to optimize. The job is to make sure the numbers are perfect and every scenario is covered. It’s a bottom-up skillset.

In consulting, you’re given a vague question, then expected to figure out what matters, where to focus, and what you can safely gloss over. It's fundamentally a top-down skillset

PE requires both: the top-down strategic thinking for owning and growing a business, and the bottom-up numbers rigor banking drills into you. Bankers usually have the technical skills PE values, but often lack the strategy mindset that can only be refined by working through ambiguous problems with other strong problem-solvers providing feedback. Given that, the consultants in PE are those who’ve also built those core analytical skills, but naturally excel at navigating ambiguity due to their training

Ironically, it's related also to your hiring process.

Formulaic hiring (LBO tests and case studies) and you select for formulaic people. Play silly games, win silly prizes.

Why does it surprise you that people who have followed a well-trod path for 10+ years, taking bland classes, spending time with uninteresting and unoriginal people, doing boring work, have little to no problem solving skills? The creativity and problem solving skills that abound in young and intelligent people have been beat out of them by the time they get to PE assoc level. 

That’s what firms get for hiring spreadsheet bots instead of critical thinkers. Try recruiting out of the box if you want thinking outside the box.