I doubt enforcement has changed significantly. I'm more willing to believe that this is part of the slow unraveling of the social contract in the United States. Everyone hates each other, and now people are driving like it too.
- Politicians are regularly lining their pockets
- (Big) business is stretching the law beyond reasonable doubt
- those influencers get a bigger house|car|pool|party just from looking
I am not sure if this is not "everyone is breaking the rules for their benefit, why shouldn't I do the same?"
Where I grew up in Ohio, there was a lot of traffic enforcement. Conversations with family leads me to believe there is still some degree of enforcement happening in that area, But I've seen little or none in California, outside of I-5 speed traps.