I don’t think this is categorically true. A couple obvious options are constructing titanium gliders to land materials on earth, and de-orbiting incoming metal loads with a space tether to provide inertia that can then be used to launch planetary loads to orbit.
It’s true that the relative value of these materials will be higher in space (since your alternative is lifting it out of the gravity well) but there may be so much supply that you can saturate the space market and justify the extra transport cost to sell it on earth too.
Or most likely in today's scenario, demand is miniscule in space compared to earth's so you sell on the earth market while demand in space materializes.
If you make water cheap in the orbit, and have capability to produce fuel... it would drive investments into space through the roof.
Suddenly you only need to get to orbit, as everything else is cheap, because you can refuel and get water. You can go where you want to go, you can grow food, you can stay in low earth orbit for cheap.
It’s true that the relative value of these materials will be higher in space (since your alternative is lifting it out of the gravity well) but there may be so much supply that you can saturate the space market and justify the extra transport cost to sell it on earth too.