What if zero g is the best or only place to manufacture something? Varda grows crystals in space to make medicine that works better than when grown in a gravity well.
That is a valid argument but so far I'm not aware of anyone doing the complete calculation of what that could entail and which exact medicine could be cost efficient to manufacture like that.
But if that would be a real market case, then Elon's solution is actually the optimal one, and very similar to the possible approach which more knowledgeable space analysts said for years. Basically it is super pointless for humans now to have big manned space stations for any economical purposes. We should build them of course, but they will be a net loss for centuries. If any space research or space manufacturing would be required by the market, then one-off space missions are the only rational way to do it cheaply. Something like the platform showcased here, or something bigger, like a converted Dragon/Cygnus/etc. ship into a mini lab. Commercial Space Stations is a bunk program, specifically in the word "Commercial".