I understand where you're coming from, but I can't justify paying the Prusa tax lol. Don't get me wrong, I would consider getting one, but my usage just isn't that high.
Regarding your development point, there are several open-source projects like Marlin or Klipper that are free to use for 3D printers. Even Prusa uses a variation of Marlin as the base for their firmware, though they modify it to fit the needs of their printers.
I'm not entirely sure about this one but couldn't they simply use Prusa's firmware if its a 1-1 clone, eliminating the need for additional development costs?