I think it's a combination of fallout from the pandemic and BLM protests.

During the pandemic traffic disappeared. If you were one of the unlucky few who still had to go on-site to work, the first thing you noticed was there was no traffic. What was a 1.5 hour commute previously was a 45 minute commute during the shutdown. When people started driving again it was like they all forgot how to do it.

Regarding the change in driving habits, the most dramatic example I've seen is people crossing the double yellow line to pass cars. I never used to see that, but it's almost routine now. I've seen people do it in areas where they can't even see oncoming traffic. Crossing over into the other lane to pass 20 cars sitting at a red light. It's insane.

Apart from all that there's also so many more people with their eyes glued to their phone when they are driving. You see someone swerving all over the road for miles, and if you get close to them they are always looking at their phone.

EDIT:

Re BLM, in some cases police policies directed officers not to get involved in traffic stops. In other cases, I think butthurt cops decided if they weren't allowed to abuse brown people, they'd just refuse to do anything.