Because Walking dead did everything better

Walking dead was a better game...in every way

Also QTE's were not 'called'(I assume you're saying they were discredited?) in Heavy Rain. However the boring scenes were. Along with the plot holes and cheap tactic with who the killer was.

Theres no right wrong way you can do quick time events...unles it's like RE6 when they are used all the time

The Walking Dead was also more of an indie game that was sold in chapters. It's whole design was to be played like that from the start. Heavy Rain was marketed as having beautiful graphics and pushing the PS3 hardware.

David Cage was also trying to push the boundaries of games and be more emotional but that kind of backfired because the game was a set piece with him pulling the strings. The gamer never really felt like they were in control. Also the QTE were not very engaging a lot of the time. The Walking Dead's QTE were.

So when you have a large budgeted game for $60 people have higher expectations. So yes, you do have different sets of rules. Are you really going to argue about the car physics in Gran Turismo compared to Calling All Cars?