Except you don't have to have the sub for the entire time you are developing, you can sub for a month and the continue to use that version of the engine. If they release an engine update that you want you can just sub get the update and then unsub again, they even say so on their forums.
Plus your math is off, if you sold that many games at that price you would have made $86,175 after full sub and royalties (not counting extras like distribution costs.)
Ark_
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All I want to do is rig models 24/7 in blender. Ah it would be a dream come true. I'd have so much fun!