It's the limitations that cost money. They are code and might require maintenance.
It doesn't seem like it would, but I have found myself in plenty of situations where I couldn't give an "easy" feature or fix an "easy" bug because of some design choice that was riddled throughout the code. No idea what it might be, but I could take guesees.
The maintenance cost is probably small for them, but not to support a customer paying zero.
