The transportation and extraction costs are sufficiently high
This may be half-true if the vision is mankind going out there and mining and refining, but if it's done the sane way, the way it of course will ultimately be done -- which is by solar-powered robotics with self-repair capabilities along or incorporated -- the initial (and total) cost will be irrelevant due to the profits maintenance-free, zero ongoing-costs, self-repairing operations will continuously produce.
As for "transport costs", really, WTF? What about gravity? Inertia? Orbital mechanics? Ion drives? Sunlight? Did he forget his fundamental physics?
Mine it, refine it, and kick it - not very hard, either - (using an Ion tug/pusher that just starts it on its journey-to-wherever and then returns to the operation) towards where you want it to go, past whatever you want to use to give it more or less oomph, and it'll (eventually) get there. And once the first such package arrives after the initial latency caused by transport time, the others will follow at reasonably similar intervals to the kick-out intervals, assuming only that where they are being sent to isn't moving under its own power, in which case, every "kick" would have to be towards somewhere else (and you'd have to know where the target was going to be on receipt, too, or there wouldn't be any receipt.) Still, that's not going to be the critical use-case -- this is going to be almost entirely about sending materials mined from nearly zero-g environments to planetary and moon orbit, to the surface of the moon, to earth, to mars, etc.
If we're talking about delivery through an atmosphere, then a re-entry container, perhaps even a lifting body, will be required from some things. So an operation has to be set up to build those as required and send them to the mining sites in that case. Unless we just want meteoric delivery, which might actually be practical for some things, particularly high-temperature-tolerant things. Aim them towards a sufficiently deep part of the ocean or man-made body of water built for the purpose, rake them up at set intervals (during which none would be incoming, obviously) and there you have it. Any such containers or lifting bodies should (again, obviously) be built out of something we can re-purpose, as they are also nothing but materials mined for free in space, albeit not exactly raw materials. Heck, you could probably just make hydrogen balloons that come in slowly and let them float down to a reasonable altitude and then puncture themselves when they drift over a designated receiving area -- no massive influx of reentry heat there. Have to be some damn strong balloons to tolerate being inflated in a vacuum, but our materials science is working on that already. Not to mention other mechanisms that may be possible. :) We'd probably end up with too much hydrogen, lol. Still.
Sure, the initial startup will be much harder if they push into it as a manned operation that needs constant support and staffing. But the endgame here, indubitably based entirely on zero-ongoing cost-robotics, is almost unimaginably profitable in terms of both money and materials gleaned from these operations.