The concept of taking something from outer space and selling it may seem, at first glance, to violate UN treaties. When one takes a second look with a far more 'open' view it becomes clear that we are and have been doing just that for a long time.
Is there significance in how space resources are brought to Earth? Just like anything we do here on Earth, what we do in outer space will be done in a myriad of diversity. The harvesting of Earth based resources is so diverse, it can involve everything from digging holes to building dams and everything in between. I believe the same is and will be true of space resources.
"No nation may lay claim to a stellar body ..." is a partial quote from a treaty regulating space activities. Does that include claims to "part" of a stellar body? I argue that this has already been violated. There is a constant influx of resources from space to Earth. Some of these resources are being harvested every day buy individuals, corporations and nations. Solar energy, or the harvesting of photons, is a common practice all over the world. This practice is in fact the harvesting of resources from the sun .. a 'stellar body'. Another example would be harvesting meteorites. Asteroid material constantly bombards the Earth and many seek to gather the fragments that impact upon the Earth.
In both examples above, there is a conscious effort to gather and use or sell resources that are not natural to the Earth. These resources were, at one time, part of a 'stellar body' and have through some means been brought to Earth. I question, what difference does the 'means' of bringing the resources to Earth play in this practice? The harvesting of solar energy is also done in outer space by satellites and other space craft so why can we not also harvest asteroids in space?
I say we have, we can ... and we will!