[withinboredom]

Another problem with bringing big rocks back from space, is that you’d probably have a bunch of people trying to stop you either with words or force. Big rocks coming to earth could mean the end of life on earth with the smallest of mistakes or accidents.

[elihu]

Depends on how big the rocks are. The Tunguska event (not an end-all-life level of catastrophe but definitely not something we'd want to repeat on accident) is thought to have been caused by something that was about 100 meters or so [1]. Compared to light-weight spacecraft that's a lot more mass than we're accustomed to moving with the technology currently available. Also, the destructiveness of that event may have had a lot to do with the relative velocity of it with the Earth, which would presumably be a lot lower if you were just trying to aim a metal-rich boulder or bundle of processed metal into a parking orbit with Earth.

It would be reasonable to expect some level of concern from the governments of Earth that even relatively small metallic objects could be used as effective weapons if lobbed at specific cities or military installations. Perhaps heavy manufacturing will for that and other reasons be kept away from Earth orbit and instead be done in, say, lunar orbit or in one of the Earth-sun Lagrangian points where the gravity well isn't so deep and it's easier to move the product anywhere else in the solar system.

[1] https://en.wikipedia.org/wiki/Tunguska_event