Oshkosh does have ATC and works fine. They CAN see the traffic, tell you whether the hold is in use, which marker to land on the runway and more.
It sounds like ATC procedures were suboptimal at the PFA rally, but that shouldn't be a reason to get rid of it.
If these events get busier one day someone is gonna get involved in a mid-air.
I only hope this doesn't happen before ATC is brought in.