There are a number of reasons behind this, one of which as you point out is the aspect of a winning product.True, but when I started going in the 80's, we didn't care if we were uncomfortable for 3 hours (e.g. 5 people sitting in the space of 3 seats) because we were watching a championship team.
That said, even the best programs have struggled with putting people in the seats. In the 1980's, there wasn't an expectation of comfort when you were at a game. Metal bleachers would have been the norm with hard seatbacks possibly being the luxury. You also didn't have wide access to televised games where you could watch from home. If you were lucky enough to have a game on TV, the broadcast quality would be nowhere near what we get to enjoy today.
The home viewing experience has gotten significantly better over the last 20-30 years. The game has also been curated for television. It is only recently that schools have started taking seriously the upgrades that are needed to the live viewing experience.
