TBH there have been matches were I have left before the final whistle. Mainly the CL matches and the odd PL evening match, if City are winning comfortably, which Is pretty much the case for most home games. I’m up the next morning at 4am, and in work by 5am. But as a rule I stay until the final whistle and applaud the team.
I’ve noticed people are leaving earlier and earlier. It used to be just before extra time. Then it was 5 minutes before full time. Now it‘s 10 minutes before full time. And in some cases earlier than that. Maybe they are going to the toilet?
As you say, leaving early has now become part of the match day routine, like staying on the concourse drinking, etc, for many of our fans. Once people get into a habit and a routine of doing something and it works for them, they won’t change that habit or routine if they feel they don’t need or have to. We just have to accept our fanbase and their priorities have changed. Leaving the match early, avoiding the traffic, and getting home earlier is now a priority for many of our fans.