From a purely psychological perspective, people can’t live in a state of fear indefinitely. The other issue is that most people are becoming extremely fatigued now. Morale is down and most are trying to claw back any sort of normality they can.
Of course there are people still frightened, but the majority who were in March, just aren’t now. Possibly because they now know people who have had it and been fine and partly because most who get it severely or die from it are elderly or vulnerable. I know there are exceptions of course.
These aren’t my views, but I’m pretty sure this is one of the biggest factors we aren’t seeing the same compliance as in March.