The more I think about it, the more convinced I am that there will have to be a free option, at minimum for onsite guests (like universal), and it has nothing to do with people being priced out. I think WDW would actually be asking their best customers to go elsewhere and here's why.
The average length of stay at WDW is 7 days. Personally we go 10-14 days (our first trip we were offsite, all hated it because of the lines, 5/7 of us never returned; DH & I did return to try EMH, loved it, went repeatedly), with early mornings, pool afternoons, and leisurely park evenings sometimes. It's a nice, relaxing two weeks. Thoughts on how we will vacation if FP+ (paid only) comes to existence:
1) If the daily price at a park is now $400-$1200 extra, I will want to get value out of that. Bye bye breezy pool afternoons (one of my favorite parts). If I want to go to the parks as many days as I use to, it's $4000-$12000 extra.
2) I don't want to lose breezy pool afternoons, so I'll just do 4 park days instead of 10 since I can do everything easily if we buy passes and won't need EMH/FP+/14days.
3) If I can do everything in 4 park days, I only need 4 days at (expensive) WDW, not 14.
4) If I can stroll in when I want, pay to do rides when I want, I may as well stay at an awesome offsite resort. Thinking could end here, and you just saved thousands off your vacation even with the expensive passes with only 4 days at Disney vs 14. Disney changed your trip - not you. That choice would lead to this type of decision for many people who stay for a long vacation. Here's my own personal next thought:
5) But I don't want to do an entire full day at the park with young kids. What if they are super cranky and I just paid $1200???
6) Universal is now best and cheapest (by far) option for an extended vacation. Hello early mornings, unlimited express pass at a deluxe, pool afternoons, leisurely park evenings (WDW is now way overpriced for a pass similar to universal and offers way less than they use to with no ME, no dining plan, no EMH, expensive FP+).
I'm not even mad at WDW if they do this. I'm not priced out. I just would prefer Universal, because they offer all of the things Disney offers now at $4000-$12000 less.