My guess is many of the fans aren't watching as many matches as before and maybe not as much outside OSU as well. A lot of close matches that sometimes were decided be close calls that could have been either way across the country at this level.
In my opinion, The gaps between a BIG 10 starter who doesn't qualify for nationals and one who does is pretty thin. Then the gap for a qualifier and an all American is once again pretty thin. Now some of the top guys have their own echelon, but even then there's not that many in that group.
