Given the lack of decent parking or public transport options around the ground, the mad traffic and the distances that most people have to walk from either once they have "got there" (1 or 2 miles apart from the tram stop and the rubbish official car park), expecting all people to get there an hour earlier would possibly mean then leaving (a local) home 2.5 hours before kick off. Which is mad and unachievable for many in many different circumstances.
It takes me maybe 20 minutes to drive from home to the etihad on a light traffic non match day. I left home an hour and half before kick off yesterday. Went straight to the ground and a combination of traffic, rubbish parking options and mental queues meant I just sat down as they kick off. All with going straight to the ground and not stopping for anything.
It's not on asking people who live relatively locally and are going straight there to leave 2 hours plus before kick off time.