GPL's ideals are good. It's just that the ideals are hard to achieve when there's a need to also make money. I would describe MIT style to be 'free to exploit me [the software] as you please, even if you don't intend to contribute anything back'.
So if you got it free, it is fair to redistribute free or charge for it or whatever. But if the original author sold it to you for $40, you must sell it for at least $41. There's no royalties; all that money is yours, it just means you can't compete with the original author on price alone.
idk tho i gotta think about it
Also, this is assuming your initial software is worth "stealing", it has to be good enough first, which Blender is nowadays.