What's the deal with LA?

After my graduation the very first interviews I had were in my home town, LA. Every single group wanted to know "my network" and where my alumni was / and how big. I was a bit surprised to hear those questions because I was just a grad, not some rainmaker.
then I interviewed at WME after an internal referral (most of my friends work in media/ent) - same question.
When I networked with a few people they explained that "this city runs on a network", "hard to meet the right people", "you have to be popular", etc

Moved to NYC and landed my job.

Moved back to LA later, but still couldn't break into banking in LA.

(But I am interviewing again within the media space).

Having spent so much time in SoCal, I have to admit it is a wide, open city with a lot of distance between places. It is far more difficult to "run into someone" or "network your way into a group or client" unless you already are running in that circle. Maybe this is influenced by the media industry or this is how things are done in LA. My friends always talk about how they do stuff, and it is almost always a friend, buddy, reference, client or similar.

they have weird sex parties. they don't want any questions

Associate 1 in RE - Comm

How do you prove that you're serious about committing to the city?

Put your friend's address on the resume where you're sleeping on the couch. 

I understand the frustration, so perhaps I can shed some light on why this is the case.

For students / prospective summer interns, one issue is that we (I'm going to refer to LA firms in general, not just my bank) get a lot of tourists who may try LA out and decide they want to go back to NY full time, or are using LA as a second-choice because they were unsuccessful elsewhere. The huge issue with that, as you know, is trying to recruit someone else full-time (e.g. after a summer intern turns down your full time offer) is really difficult because the pool of acceptable candidates has shrunk a ton, especially in LA.

For full time positions after graduation, it's kind of similar in that we want to recruit people who will stay with the firm. If you haven't lived in LA before, there may be a lot of challenges you may not be used to and again, firms don't want to be a stepping stone to where you "really want to be." 

If you're not getting past this question, you simply haven't crafted a good enough answer. First, why are you serious about committing to the city? If you're interviewing for CRE, full disclosure that I don't work in that business, but I would make sure to emphasize the aspects of LA's CRE world that really interest you, and that while you don't currently have an extensive network here, you are serious about developing one over the long run which is why you're interviewing there. Mention you have visited there a bunch and love the (fill in the blanks and be truthful, if you're a beach person say that, if you're a foodie say that, etc). Say that you have friends / alumni from your university who live in LA and tell you good things about it (again, if you can point to specifics it's better). 

Tl;dr craft a better story and really look inward into why you want to work here. In banking it's actually enough if you mention you're interviewing elsewhere / interested elsewhere, it's an instant ding at many banks.