I used to live in LA. I have little interest in returning.
Traffic is really bad. Even local streets are packed, especially on the westside. Hollywood, Westwood, Santa Monica, downtown--it's almost always jammed.
The air is relatively clean compared to when I was a kid, but it still isn't *that* great. During the summer, the San Gabriel mountains sometimes just disappear behind a haze. Coastal air quality is definitely better overall, though.
The LAPD is so unbelievably corrupt as to be essentially a taxpayer-financed gang, and the politicians at the top--Republicans and Democrats--are all in on it. It's about money and power, not serving the people. People who have not lived in the poorer areas of LA really have no clue.
Like in Manhattan, the wealth disparity is glaringly enormous: everywhere you go, you can see signs of ostentatious wealth combined with abject poverty, and the longer you are exposed to it, the more you begin to think that this is "normal" and "acceptable." This sort of cultural attitude transcends political ideologies in LA.
The gay community is huge, but in sharp contrast to other major gay areas like the Castro, West Hollywood inherits a more superficial, status-oriented, looks-oriented culture from the surrounding LA celebrity and pop culture. Yes, gay men tend to be vain and narcissistic and obsessed with appearances no matter where you go, but in LA, it seems especially amplified.
LA will never really go the way of Detroit--the entertainment industry is too big here, and unlike the automotive industry, I don't see China exporting $200+ million blockbuster films to a Western audience anytime soon. That said, the wealth gap is increasing in LA, and the outcome of this is that there will be more polarization as the middle class shrinks and the suburbs decline. The wealthy will live in their mansions in Malibu, Brentwood, Hollywood Hills, and Bel Air, insulating themselves from the rest of the city as they tool around in their luxury Teslas, complaining about how the city needs better public transit because the traffic is so bad...as long as it doesn't go through THEIR part of town.