Asteroid mining I think is one of the most interesting initial space industries. Something silly like a single asteroid having metals with current valuations of a million times the global GDP. Obviously you can't sell for that much but asteroid mining could make a lot of commodities become insanely cheap, and that would enable some pretty amazing things here at home, and in space.
Like what if steel were cheaper than plastic? If there was enough of it around to build a bridge between New York and London? If you could build a ship the size of Manhattan and then a city on top of it to roam the oceans? If you could build entire cities in orbit or city-ships that slowly wandered the solar system.
Yes, send up the robot miners. Plow the results onto the moon a safe but close distance to a base. Manufacture parts in lower G and far easier vacuum (it's super useful for MANY industrial things). Possibly even use solar collector ovens to melt/cook.
Returning bulk products to earth might not be viable in the short term, but this could really bootstrap what we do off planet and I'm hopeful it might eventually make space elevators viable which would open a lot of options.
Think of all the science you could do with asteroids! Peer into the early history of the solar system . . . see what precursors to life existed before Earth was habitable. . . and all people think about is how fast they can strip-mine our extraterrestrial heritage. . . All that belongs in a museum!
Like what if steel were cheaper than plastic? If there was enough of it around to build a bridge between New York and London? If you could build a ship the size of Manhattan and then a city on top of it to roam the oceans? If you could build entire cities in orbit or city-ships that slowly wandered the solar system.