It's all contingent on a factor of 100-1000x reduction in launch costs, and a lot of the objections to the idea don't really engage with that concept. That's a cost comparable to air travel (both air freight and passenger travel).
(Especially irritating is the continued assertion that thermal radiation is really hard, and not like something that every satellite already seems to deal with just fine, with a radiator surface much smaller than the solar array.)
It is really fucking hard when you have 40MW of heat being generated that you somehow have to get rid of.
The ISS makes almost 250KW in full light, so you would need approximately 160 times the solar footprint of the ISS for that datacenter.
The ISS dissipates that heat using pumps to move ammonia in pipes out to a radiator that is a bit over 42m^2. Assuming the same level of efficiency, that's over 6km^2 of heat dissipation that needs empty space to dissipate to.
That's a lot.
(And of course, the mostly reusable Falcon 9 is launching far more mass to orbit than the rest of the world combined, launching about 150 times per year. No one yet has managed to field a similarly highly reusable orbital rocket booster since Falcon 9 was first recovered about 10 years ago in 2015).