The problem with MM/FP+ is when you outsource the work every time you want to make a change you have to go through contract negotiations/scheduling/planning with a 3rd party. They might very well want to pull in all these paper return times into MM+, but making changes like this to the backend, website, mobile apps, etc. takes time. Also probably why you have to go to a kiosk to get your 4+ FP for the day.
If they did more in-house they could probably get things like this implemented quicker.
The real problem is as massive and complex as the system is, it is realistically not possible to adapt it quickly to unexpected changes in the park.