Disney already has an essentially unlimited FP system, which is the VIP tour. This is not front of the line access, but unlimited FP. We have done this VIP tour several times, and literally rode SDMT 6 times in a row one day when it was the family's favorite ride (plus a bunch of other rides at all 4 parks). It is really, really expensive compared to other FOTL passes like Universal, I think. It does depend on how many people are in your VIP group (up to 10), as to how the price gets divided per person, so the cost can be brought down somewhat (though then you have to agree on what rides to do since the VIP guide can only be in one place at a time, getting you on a ride, for the most part). Most VIP groups I see are 4-6 people (we are 6), so if it is $4000 for 8 hours (more than that during holidays, plus tip; more if you go over 8 hours and want to do the "full day" of VIP like Universal's pass would give you), then that is $666 per person, PLUS theme park admission (with Parkhopper in our case, though you could just do one park, I suppose). Before tip and not at high season. If WDW rolls out a true unlimited FP, I think it will have to be basically prohibitively expensive to make it worth it (if the cost is too low, "everyone" will get it, and FP lines become SB lines). Based on the pricing of the VIP, you can see where they think the price value is, per person.
I actually talked to our VIP guide about this in March when we were there, and she said she hopes they never truly monetize FPs because she will lose her wonderful cushy fun job! While I get her point, WDW will eventually decide it is cheaper to sell me the unlimited FPs directly and not have to pay a person (and their benefits) to walk around with me to use the FPs. While the inside information about the parks that the guides offer is wonderful, the reality is people are paying $4000-$5000/day (plus park tickets) to get FPs and VIP seating at shows/parades/fireworks, etc. And that "access" can be added by WDW to my MB for $0 to WDW.