Peering into my crystal ball:
There is also the assumption in the OP's post that so many guests are unhappy with FP+ that Disney is being negatively affected and will eventually have to change. That doesn't appear to be the case. From the prepared remarks in
last week's earnings conference call (emphasis added):
For the quarter attendance at our domestic parks was up 7%, with Walt Disney World and
Disneyland Resort,
each setting an all-time attendance record for any quarter. Per capita spending in our domestic parks was up 4% on higher
ticket prices, merchandise, and food and beverage spending. Occupancy on our domestic hotels was up 8 percentage points to 89% and per room spending was up 4%. So far this quarter, domestic resort reservations are pacing up 3% compared to prior year levels, while book rates are up 4%.
Later in the call they also talk about being happy with guest response to the MM+ intitiative. That could be a bit of spin, but it's generally unwise to out-and-out lie on an earnings call.
Quite a few folks are convinced that, given enough time, eventually Disney will see a downturn in attendance and/or spending due to dissatisfied guests, and we just haven't had enough time for that to happen. But, FP+ is almost at its one-year anniversary of full roll-out---that was right around the end of March 2014, and the 4th-and-beyond capability was added about a month later. Even among the DISboards, the number of people who are *actually* not going back to WDW (as opposed to saying they won't) seems to be small. They may be going less often, but there seem to be plenty of people willing to take their place, given attendance and occupancy numbers.
I suppose it could still happen, we'll have to see. But, from where I sit we are getting close to the end of the window of uncertainty.