Interesting point. If they allow guests to make their 4th 5th and 6th FP+ reservations via mobile app, Disney will effectively shut out first time visitors who did not know about FP+ prior to arriving at the parks.I'm starting to doubt this is in the cards. Disney surely has the IT capability to do it now, but perhaps they are holding back for fear that afternoon FP availability will dry up immediately if they let people book 4th FP on mobile devices. This may be an intentional hurdle.
Remember Disney's target audience is educating the causal vacation goer, particularly the first time visiting family, trying to minimize their overall wait in lines to get them to return. They have been successfull in so far as a much higher % of these folks know of FP+ than they did of legacy FP, do the detriment of people like us.