Seriously? No idea! I would have a track record on steam, but I doubt any of those are the games I've spent the most time. It seems on steam the most I've played is EU4, which has about 933 hours, but that number might be a bit inflated on account that I spend a lot of time with the game open doing nothing. 

Although, it is rare for me to spend more than the average game completion time for the games I play on ps4/ps3/ps2. Due to their nature, and lack of replayablility I wouldn't be surprised if those numbers about below 100 hours, even for game like Skyrim and Fallout. I could go on a long rant about the difference between buying a one time experience and a grinder, but I'd rather not.