I don't think the conference had that many tie ins back when they still had Louisville, Cincinnati, etc. Back then I believe they only had 4 tie ins. They've added a 5th, and I believe the 6th tie in was added prior to the 2007 season.
I doubt they lose too many tie ins unless bowls start folding. The main reason they have so many tie ins is because there are 30+ bowl games, and the bowls need to guarantee that they'll actually have a team to play in their game.
C-USA is reaching a whole new level of suckitude though. Outside of a few quality baseball teams, Memphis in basketball, and a rising UCF football program, they really have absolutely nothing to write home about. It's really an awful conference.