So a single source has the high number 7 trillion, which doesn't include over how long this amount will be invested, the structure of this initiative, etc. I think people read this and think the gist is "Sam Altman is requesting 7 trillion dollars personally for OpenAI to build chips right away" like it's another funding round.
I think the general premise is that he anticipates that much money will be needed to get to ASI compute and he's citing the amount now so people are apprised of the scale. Until more explicit reporting emerges the speculation seems to be more revolving around people's seeming dislike/disillusionment with AI and its impact on tech than the actual facts.