Police no longer bother with poor driving unless they're on an "initiative" to target particular things. Go back to, say, the 80s and all police would pull over a car driving badly, blown light bulb, speeding, etc - usually just to "give advice" rather than reporting them. That was ALL police, including section patrols, foot patrols, dog van, etc. Nowadays, it's only the dedicated traffic police who seem to bother at all, and then only when it's something very serious. "Normal" local police are happy to drive on and ignore things - their training is probably dumbed down so they won't know what offences actually are unless they're trained specialist traffic police!
That leads to more and more people not bothering as they know they're not going to be stopped unless they're doing something really serious. That leads to everyone else thinking the same. When you regularly see other people go straight through red traffic lights, you're less likely to make the effort to stop yourself if the lights are just changing. Same with speeding, when everyone around you is ignoring the speed limits, you think "sod it" and do 35 in a 30 limit yourself! Then the same happens with illegally spaced personalised number plates - no enforcement so no one cares and more people do it.
Or people parking on double yellows, blocking dropped kerbs, parking too close to junctions etc at night and weekends because they know the local council parking wardens only work 9-5 Monday to Friday!
So many cars driving around (especially Just Eat etc) that are untaxed, or no MOT, or no insurance. I once did some online checking whilst parked in a McDonalds Car Park and nearly ever other deliver driver car either had no MOT, no insurance or no road tax - probably some of the drivers didn't have licences either. An easy "win" for police to park and check, just like I did, but they can't be bothered!
At the same time, we have "remote" law enforcement, i.e. speed cameras, bus lane cameras, traffic light cameras, etc., that are just revenue generating cash cows which alienates generally law abiding motorists even more. You get a ticket through the post for accidentally straying into an empty bus lane in an unfamiliar town (each town have their own rules as to times you're allowed in bus lanes etc which isn't helpful and set to catch people out), but then see some boy racer speed through red traffic lights. It creates an environment of annoyance and unfairness.
Quite simply, the enforcement of traffic/road laws is wrong in so many ways, absent in so many ways, etc. Until the councils and police get a grip and start enforcing laws properly and in a fairer more logical manner, things will only get worse.