But I don't think you can ascribe this to simply being distracted nowadays by cell phones. You still see people focusing on the game itself for the most part. There are two additional (larger, IMO) factors at play:

1. Marching bands aren't perceived as entertaining nowadays. Could be a generational thing, could be the fact that other forms of entertainment dominate it, but it's the truth. You won't see people sitting after a game for hours listening and cheering with the marching band.
2. I'm sure band members put forth a ton of effort. But the BYU marching band is outdated and boring compared to other marching bands. We've seen other marching bands, likely recognizing #1, adjust the way their entertain. BYU, OTOH, does more-or-less the same thing, year after year.

I do appreciate an insider's perspective.