The big problem is that RCI is renting a lot of its inventory to non-members and that means less exchange inventory for members. That started in a big way when they created RCI Points but it had been going on to some degree before that.
When I was an HOA president on the NC Outer Banks of an independent resort, our manager noticed some very odd codes for home resorts on RCI Inbound reports. One of them on checking in mentioned they had rented from RCI and further that they had never been to a timeshare before, so our manager then started casually asking those with the odd codes on check-in what their home resort was, and it turned out everyone with the odd codes were RCI rentals. I asked her to analyze what weeks were being rented and it was mostly prime summer weeks that exchangers would be eager for. Every one of those weeks had been deposited by our owners into the RCI pool for exchange, but RCI was taking them out and renting them instead.
Also, when I exchanged into a London resort, Sloane Garden Court, through SFX, I talked with the manager there who told me that after RCI went to points, they found that RCI was renting out most of their members deposits instead of offering them for exchange. The resort found that renters did not take care of the units like exchangers did, so they dumped RCI as their exchange company and started exchanging exclusively through SFX.