That really depends on the assumptions you’re making about why it’s done. Large scale mining for building materials and fuel requires an existing space industry

That really depends on the assumptions you’re making about why it’s done. Large scale mining for building materials and fuel requires an existing space industry for demand. Saving on Dv only makes sense if you have something proven so out there... like mining. Either way there needs to be a truly enormous initial investment in propulsion, and so much more. Making an absolute fortune, and/or breaking foreign control over vital resources could be the key to getting that funding.