Exactly this. Epic could not just drop FBX support because there are lots of Max / Maya users. But it seems 10k are too less to workaround those GPL vs non GPL-friendly proprietary standard (by design) and file format issues (like implementing the same stuff in 2 different ways for Max and Maya in one fileformat). On the other side… if some had enough money to implement a further game engine (Stingray) which costs way more than a 10k donation into their product (and which competes now with UE4) maybe others have enough money to support a further (open) fileformat in their game engine. Currently FBX export of Blender works for UE4 (so far it seems there was a step forward - especially in the later releases of Blender). Import is still messed up (which hurts but is no showstopper). Would be interesting how that affects plugins and forks around Blender like Darkblender or GEX