Hours wise it's not the fastest. When I finished Oblivion's main quest, I was somewhere around 90 hours as well. But even though I bought Oblivion when it first came out, I didn't actually finish the main quest until some point a few months ago (August, I think it was). I got a good chunk into the main quest when I first got it, but computer issues made me lose my progress. After getting a new gaming laptop, I again gave the game a go (after a bunch of attempts at characters that didn't stick), and finally got even further into the main quest, before once again having computer issues and losing my progress. When my laptop finally blew up, I eventually just bought it again for the X-Box 360 and finished it up finally this year.
With Morrowind, I didn't track my hours, but I'm sure it was somewhere along the same time frame in terms of hours. But I took at least 2 hiatus' from Morrowind before finally completing the main quest, and probably had the game for over a year before I finally finished it (I also got it when it came out). Unfortunately, that character is also gone now too, so I can't even go back and revisit him
In terms of my own personal Elder Scrolls canon, the Nereverine in my timeline is now deceased.But I finished up the Skyrim main quest last night. Unlike with Morrowind and Oblivion, I was able to get through 90 hours of gameplay without taking a break from the game. I still feel like there's a lot I'd like to accomplish with this character as well, so I may have a ways to go with this character yet.

