This is especially good QotW, with profound implications which
merit an essay.
However, quickly, in response to your key observation:
Right now, with this level of attendance, the loudmouth who yells
out "You suck, Celaya" (or similar) is the prevailing
voice. But when you have thousands of fans reacting intinctively
on each play, those guys are pretty much drowned out.
They go from center stage to minor off-camera annoyance. Big,
big difference. And that's important because the current atmosphere
would be a turn-off to the curious newcomer who just walked in.
But the 5000 level is just the opposite - a breeder reactor creating
new fans on the spot
Most of the fans who post here got started when the attendance
was like that. It's not a coincidence.