My 2 cents:
I was in the crowd that blamed Holtz and losing on our lost attendance. We drew big crowds in the Big East, I thought they would return... they obviously did not as evidenced by our first home games this season. Winning, ranked, and competing for a CC and NYB obviously mean nothing to our missing 'fans'.
So what else could it be? I am starting to think we had too much success, too fast as a program... which created a false appearance of support and legit fans. I don't believe we, today, actually have a real/large fanbase.... no matter how many students or alums live in the area.
We went from nothing to FCS, to FBS, to BCS, to beating big time ranked opponents in essentially a decade. That incredible rise generated a LOT of excitement in the bay area... and led to those big crowds at RJS. We had better crowds in our initial years than we did last Thursday night!
But obviously that paper/bandwagon fanbase could not tolerate losing, and demotion to a non elite conference. They are gone, and even winning, ranked, competing for a NY bowl are not going to bring them back.
It's a shame, but I don't think an OCS stadium helps at all... in the near term. It just moves the empty seats to campus. We all know from the late 2000s that everyone knows how to get to RJS. They just don't want to go attend now, no matter how much we win against 'smaller time' opponents. Crying shame.
At this point, our current support is not sustainable for us as an FBS program. Tallybull made a brilliant point above, you have to build the OCS as a requirement... you can't wait for better attendance at RJS to justify the need. It's clear the fanbase is gone, we are starting at baseline. We need to BUILD a new fanbase. That will happen on campus, or not at all... given our current conference. We can't rely on big (Big East) opponents to bring in visiting fans anymore.