SE doesn't decide these things, players do. Most people would bail so fast on a run that even looked like it might take 90 minutes that that sort of play would never be tolerated.
Heck, even the duty abandon penalty doesn't function any longer if dungeons are taking 90 minutes - it's only a 30 minute penalty. It would be infinitely more efficent to abandon such a group of players. Not only would you likely complete your next run of that instance/roulette faster even with the 30 minute penalty applied (because I cant think of a dungeon that even takes 30 minutes without huge mistakes) but you also have 30 minutes to craft or otherwise make use of your time.
So no, the 90 minute time limit means nothing at all.
I really dont get how someone can advocate for politeness while also admitting to wanting to waste other people's time. Nothing more rude and entitled to thinking that your time is worth more than other people's.
