IMO, these neutral site games are a good way to tell where the fanbase is currently at with the program. State Farm Center attendance is always going to be a lagging indicator, because those numbers are strongly buoyed by season ticket sales. Fans are attached to their season tickets. And, as soon as you don't buy season tix for a year, you lose all seniority points - not like they're worth anything now, but fans renew in the hope of having them worth something someday. It's tough to give those up (and that's why I still have them!).
The neutral site games aren't tied to that, so it's just a matter of how attractive the team is at that moment in time. 10-15 years ago, we'd fill a gym in Hawaii with orange for some game in December. Now, we can't draw flies in Chicago, let alone New York or Miami. We don't draw casual fans, and even season ticket holders don't want to spend even more than they already have to get extra games.
These games are a snapshot of the fanbase, which is why I'm convinced that Groce has lost the fanbase and likely isn't getting it back. Sure, we're still selling 13,000+ on occasion at SFC, but no one is interested in the "extra" games that are optional at that point in time.
On occasion? They sold more than 13,000 just for Central Michigan. They'll be back when we start winning, whether it's with Groce or not. It's that simple.