Im not going to be too far off from that time either. And I didn't miss out on much. It probably has to do with me fast forwarding through a lof of those citizen dialogue scenes. Also fast forwarding through a lot of the group text messages since they say a whole lot of nothing.
But that would only cut a few hours at most. My biggest question is how people are finishing this game in so many hours. Unless you're repeating dungeons from dying too much or doing mementos over and over again.
Where are you even at? The game is probably longer than you think.
I completed the game on exactly 100 hours(and 11 mins) and I wouldn't say I took my time massively. There's some idle time in the 100hours, but probably not more than 10hours.
Didn't grind, and honestly I'm pretty sure I was under levelled by the final boss (wasn't that hard either way, fortunately).
I didn't lose much time from deaths, I think I lost about 30-40mins in Dungeon 5 because my entire team got despaired. Though I didn't even think that counted on the clock since it just reloads back.
I wouldn't say I spent a massive time in Mementos either, maybe 5 trips maximum to it, and most of the time was literally spent driving through it, not even fighting shadows as I found it to be boring as hell.
Honestly if people are finishing it under 70 hours I feel like they must be playing on a lower difficulty, and/or skipping through a lot of dialogue.