As someone who went with an AP, I can assure you there were enough resort guests pre-booking to essentially ensure things like 7DMT, FOP, SDD, etc. were never available to reserve after the 30 day mark save for the random might-get-luck lotto if you happened to be in the app when a resort guest who had them for the day you were looking at dropped them for some reason.
When FP+ was "free" it was annoying and meant we usually didn't end up doing anything (besides mermaid) that had opened in the last 15 year but if they're charging for it, there is no way they'll get away with that for paying guests.
When bookings are up, there are
definitely enough resort guests to wreak the system with a change like that. Think about why there was always a mad dash to get what you wanted for your whole stay the moment the clock hit on the 60 day mark for your first day.
I don't expect you (or Chai) to feel bad for the local who wasn't booking major vacations and missed out on things but the dynamic changes when people are paying money specifically for the benefit and Disney has to consider that now because if they open up anything to pre-booking, that makes the day-of purchase almost worthless except on days the parks aren't busy enough to even really need it.