West Coast Firms where suits aren't frowned upon?

If you want to be le dapper gentleman then go ahead. Just like you look down on the “bro vests” you should be prepared for people to view you as a bit of a dope for insisting on a suit every day though.

You can wear something interesting/relaxed like a nice Isaia piece or something. There are ways to wear suits without them looking overly formal. :)

To your question, I’d imagine most guys dress like everyone else at the office because they don’t give a shit how they dress, so the default inoffensive option is fine. But this is speculation on my part.

I like to look decent but also couldn’t care less about the differences between one suit and another. And not having to wear a suit is definitely a plus in my mind (although I agree Patagonia vests look pretty mid).

At a slightly more formal office and there are 1-2 guys who wear suits. People think they are a bit uptight, but if they are well-tailored and you pull them off, you do you. It's out of the norm though and you will just need to own that, not looking down on people who dress in the normal way...?

People "dress like everyone else" because a dress shirt/Lulu pants are more comfortable and practical (cleaning, expense, tailoring) than a full suit. No one is going to haze you for it lmao you just might get some comments thinking you're uptight or silly. 

Some seniors wear suits for meetings but that is for the sake of meeting clients. If they are just coming into the office they will be in casual clothes and sneakers.