Two things about your line of thinking stand out to me:

The first is a subtle implication that the share price of SpaceX is dependent on the short term feasibility of data centers in space. I don't think it is. Its more dependent on public sentiment and hype, which is detached from the truth and can have its focus directed elsewhere as the company engaged in many activities. I would also argue that the company's culture matters more than any engineering specifics, especially with how diverse their assets, competencies and offerings are. Maybe you didn't mean to infer this though.

Second, if intelligence is something like electricity, in that it's fungible and translates fairly universally into value, then it's safe to assume civilization will pursue expanding it endlessly (and will never have that demand satiated) like a force of nature. If this is true, would we rather have 1000x or 1,000,000x the data centers we have today within earths atmosphere or out in space somewhere? Personally, at that scale I would prefer them far away. (Not even in LEO)

There is no core physics reason why AI data centers in space can't work. It's just really hard engineering. Kind of like what reusable rockets looked like 10 years ago... All the experts were nay-sayers.

Short term, who knows, SpaceX could struggle financially and be a terrible investment today. I have no idea. It seems overpriced to me now and it did at IPO. But on a 10 or 20 year investment horizon, it looks a lot more interesting. I don't own shares but maybe dollar cost averaging in at some point isn't a bad idea especially if the price comes down further and as part of a diversified portfolio.