Another non-Agent answer here:
The answer is there are far more people in Los Angeles that are far wealthier or have incredible incomes that will simply make you question why you bother to work at all. Just to start: Celebrities. Actors/actresses, musicians, athletes, writers, artists. Many people who "have made it" now live in Los Angeles or NYC. Their royalties alone can generate 10-100x what is considered normal. I know they're not average, but hold on...
Step down from the massively successful a little, and even B- and C- level celebrities, producers for less successful shows and movies, still can make a lot more than what you consider normal. Then there are other media, Doctors, Lawyers, business owners. There are INCREDIBLY successful real-estate tycoons who live here, people that laugh at how insignificant Donald Trump's "empire" is worth. There are people who rent aircraft hangars at Santa Monica airport just to house their car collections. There are people who live in beverly hills houses and pay $60 GRAND a month IN RENT, and laugh because they're getting a steal because it's all going through their corporation, which probably generates multiple millions per month.
This is Los Angeles, where many of the most successful people in the world live and work. The super rich alone employ their own staff of people. I interviewed a nanny whose last job she was one of six nannies! Yes, it is crazy, but there are tons of people who can afford to live here. It's almost like Reagan's trickle-down economics, but all those ticket, music, and DVD sales, all those cable subscriptions, all those ads that people see, all those airplanes and defense that are purchased, a lot of that computer software people buy from around the ENTIRE WORLD, a lot of that money gets injected into LA's economy.
There are legions of small business owners in L.A. Successful boutique owners, building contractors, curtains, persian carpets, restauranteurs, celebrity chefs, boutique butchers, niche sausage-makers, instrument sellers, rare instrument makers, vintage car sales, luxury car sales, exotic car sales, exotic used car sales, pet groomers, pet breeders, pet walkers, etc. There are so many business owners in this town. I had an Uber driver who owned the sunglass carts in various malls, who picked me up in his Audi A8...doing Uber-X just because driving helped him think and he enjoyed networking with people. The painting contractor we hired that had the best value and most professional proposal, drove up in a 7-series; I could tell he had earned it. People spend money in L.A. and it makes a huge economy. An economy that supports ... very high housing prices. Look around L.A., you don't have to look far to find ten people who are millionaires, and they may even be living in $700k 3bd 2ba from the 1940s.
There will always be people who make more money doing less work than you. Is it fair? I don't know. Is their life any better than ours? From the outside, it would seem so, but once you dig a little, everyone I know who works with celebrities and the like are happy to live "below" that lifestyle (but are nonetheless willing to accept their money!) Money definitely makes some things more comfortable, but it doesn't make those people any happier (often less so, and there are exceptions of course).
There is a solution: do the best with what you have and be willing to make trade-offs. Be willing to live in something older, or a less desirable neighborhood. Live in a townhouse or condo, take a longer commute. Purchase a smaller house, make two kids share a room. Or you live the L.A. Dream and figure out a way to get a bigger slice of the pie.