I'm trying to imagine the pollution controls that would make that economical. And the space network that would enable it. I think that even with astronomical fines for pollution on Earth, it would be a difficult value proposition. Consider a planet made of solid gold, and then consider how far away it would need to be to make it uneconomical to retrieve. Moon rocks have been valued at $50,800 per gram based on the cost to retrieve them, which should probably be taken as an upper bound rather than a typical figure, but the current spot price for gold looks like it's around $37 per gram. So if the Moon were made of gold, we would need to reduce our retrieval costs by three orders of magnitude to make it worthwhile. I don't have a remotely rigorous way to estimate from that where our current breakeven point might be, but I think it would be pretty close in.

Your idea is pretty crazy, but not completely crazy. There aren't any other particularly good ideas for making space travel profitable. On the other hand, it's difficult to imagine the advances in technology and the environmental concerns that would make it possible. Barring some absolute prohibition, it seems unlikely that spending millions or billions of dollars to manufacture things on Mars would be easier than improving manufacturing processes here on Earth.