Elon's participation in a project produces otherwise incomprehensible valuations across several businesses. So, yeah, either all those businesses are doing OK or Elon's funders are inflating a bubble.

Since I haven't heard a peep of a complaint from Elon's financial backers about having a declining social media site shoved into their AI investment, the investors are still thinking that they could unload on greater fools when the time comes.

Well given that it's a private investment they can mark it whenever they want so it's helpful for them. It's also possible (though I don't think it likely) that xAI makes them loads of money.