North Hollywood was allegedly gentrified in the 2000s. I don't know if it's so.
Also, much of the residential building downtown was apartments. If they had built more condos then "pride of ownership" might have gotten more residents to demand more police patrols, etc.
I used to live just north of DTLA near the Music Center. It was quite nice and quiet at night. The apartment I was living in was hinting at going condo, but never did. I might be living there now if it had converted.
I have some cousins that work downtown. The parking is so expensive that they have to take pubic transport. They have bear spray to keep the homeless at bay when they walk from the bus stop to their offices.