I really thought we were at a point where you could just make the game and build it for multiple platforms without making changes.
The pay wall makes sense though.
You always gota make changes dawg :P When switching between PC, Mac and even Linux now, it's not too bad. But for mobile ya gota make touch controls works, optimize for different phone types and architectures, and sometimes even more. Not to mention testing on phones always a pain. But yes also the other reasons too