OP here and I'll be as clear as possible. Had all this mess with FP+, tiered attractions, etc. NOT been going on and it had been WDW as usual, there is ZERO doubt in my mind that we would have taken the trip instead of cancelling it. We were looking forward to it and needed a fun trip after a fairly crappy year. We looked forward to our WDW fix and suspending reality for a week or so. WDW was meant to relieve the stress, but all the uncertainty and constant changes were ADDING to the stress. I don't usually pay a fortune to have stress added to my life.
So yes, FP+ and all it entailed actually DID directly cause us to cancel the trip. Maybe you don't see it as a valid reason to cancel, but since you're not paying for my trip, your opinion as to validity matters not at all. Not everyone thinks as you do. Maybe that's hard for you to grasp, but it's true.