Why would I want to be the hero at the START of the movie? That's when I'm just doing my daily shit and I'm showing off all of my character flaws. That's the worst possible moment of the movie to be aping the hero.
Because the start of the movie is where the hero does the things that lead to their victory
You get to go through the montage section, that's the best part!
Besides, what if Dujour and Choi don’t knock on my door, never lead me to Trinity, so Morpheus never offers me the red pill? Now I’m just stuck as an ordinary schlub.
Because you want to be the one that over comes all of your flaws.
Because it’s hard to transition from daily grind into peak hero. Hence, start when the hero is ordinary, like you are (I speak of the concept, not you in particular.)