stanford won 8 games last year including beating oregon and usc at home, yet still averaged 15k fans a game (hence football is obviously not a priority for the alumni). i bet vandy does better than that. and i'm not sure what long football history you are talking about. unless you want to go back to pop warner.
i was even just thinking something at all to hang their hats on i guess; things like like elway, plunkett, seasons at all to hang one's hat on as successes...
here's vandy's football history:
Vanderbilt Commodores football - Wikipedia, the free encyclopedia
they were a power way, way back before all of us, lost it, and just stopped caring
Compare it to Stanfords results; even just from the 30s on if you want
Stanford Cardinal football - Wikipedia, the free encyclopedia
As for the attendance, in the Southeast a college football game on a Saturday (especially in old southern cities) is and has been very much a social event with people many times attending for that reason; Vandy being in a big city like nashville means it's going to still get a good deal of attendance in that environment....say compared to being located in a population size like Stanford
The comparison I would make however is look at the stadiums the schools built for football. In a region of the country where "football is god" and everyone in conference seems to have 70-80,000 at least seated stadiums, Vanderbilt's stadium only seats 39,000 and that's been its peak even after renovations. Even out west, Stanford's stadium reached a seating of 85,000 up until the renovations in 2006, but even now it still holds 50,000.
(In both cases...pretty well more than Vandy)