The commercial offerings are far more used, which means there's more tools, there's more prebuilt assets you can buy, there's more documentation and StackOverfl

The commercial offerings are far more used, which means there's more tools, there's more prebuilt assets you can buy, there's more documentation and StackOverflow answers. I would bet that either of Unity or Unreal have more dev resources going into them than all of the ones you mentioned there combined, too.