The issue with AI datacenters in orbit is not science or engineering but economics. There is no practical reason why it can't be done, but why would anyone want to buy compute from such a datacenter when they could pay substantially less money for better capacity on Earth?

Orbit is a bad place for a datacenter. Your equipment will be hot and bombarded with radiation. You can't do any repairs. Even with reusable rockets you still have to pay for fuel to launch everything into orbit. You get a small benefit of more efficient power generation but it's not worth all the downsides.

If you want to have solar-powered AI datacenter that you can't service, you'd be way better off building the power generation in a coastal desert and building your datacenter underwater.