In the 2015 Unofficial Guide, Jim Hill mentions the Magic Band/FP+ project went way over budget - a best guess would be that these features are expensive to implement, and Disney didn't want to continue to hemorrhage money. I think they will resurrect those ideas at some point, though!
That seems to have been disproven, and MM+ came in very slightly under budget. But the name thing is among the cheapest things to implement, compared to the rest of the system. This isn't just the MagicBands and FP+ that you see, that's such a minor part of the expense of it. (warning: I work in IT, this is from a purely IT perspective):
Think about this: every single hotel door lock on property, over 30,000 of them, required replacement. The entire property needed pervasive Wi-Fi capable of supporting over 1,000,000 devices ... assuming perfect distribution of access points, that's over $20,000,000 in wireless gear alone, not to mention the power systems to support them. Then there's fiber optics throughout parks that were built, at the earliest, in the 1990's, with attractions dating back to the 1970's, before Ethernet or IPv4 even existed. Then this all needed to be connected to the website, and have a transactional database capable of appearing to respond instantly, and this had to be done without guests noticing. The soda dispensers are now part of MM+, and integrate to the system, along with the drink cups. MagicBands are just what you see, but they're much the smallest part of all of this. And all of it needed to be done, too. Disney couldn't keep relying upon an analog CCTV system, magstripe cards built in the 1980's, and hotel door lock systems designed for 1,000 room hotels, not a sprawling complex.
The new bus and monorail scheduling and dispatching falls under this, concessions falls under this, everything does. This is a true IOT move, and Disney is WAY ahead of the curve and into uncharted water with this, and by necessity. They couldn't keep relying on a hodge podge of old systems, patched to make them seem modern, they needed a complete overhaul, and IMHO they did it right and didn't spend too much on it.