That's literally just hearsay in a tweet thread. The high speed rail project was never cancelled and certainly not because of any hypothetical hyperloops. Very convenient scape goat for California's terrible government though. Hyperloop was a brief headline generating concept. If that's enough to derail a $70 billion dollar project then the project was always doomed.
My God as if ideating on alternatives is enough to kill a project! What world is this? have you ever built anything?
California's "high speed" rail was still going to take 5 or 6 hours for the SF to LA route. No better than driving! Musk was correct to propose something different.
It's been 15 years since that project was proposed and we're no closer to a true high speed rail between those two cities!