It hasn't devolved, it has been deliberately regressed. If we remove the incentives for this behavior, people will naturally begin changing. This is what the Democrats have been doing for generations, and unfortunately it will take generations to fix.
The weird bit is that black people become cops at a disproportionate rate. I think it is 28% of police are black, while about 13% of the population is black. That's a significant number who want law and order.
The are being hamstrung by liberal whites, race grifters, and Democrat politicians.
There is one thing we can try, but it is a long shot.
A Constitutional Congress. If enough states get together, they can change a great many things, including creating amendments to the constitution, and the federal government can do shit about it.
This is, as you may have already surmised, very difficult to execute in practice.