Not actually sure that is true. Entirely possible that just by re-using Superheavy and expending Starship they could get to a price point lower than F9 (which also has an expendable upper stage).
Perhaps. But until it is demonstrated, unfortunately because Musk has been overstating future costs of a lot of things for a while now, we can't rely on his optimistic statements for forecasts of our own.
I'm only saying your previous "will be" is too strong a claim, not that it's completely unthinkable that it may come to be.
That said, it's not like other billionaires aren't working on the same basic idea, even if they're copying what was already proven with the Falcon 9, which is great for people who want to go to space but not so much for SpaceX investors.
