Aerospace industry has a long history of missing lower cost/kg to orbit. I'm extremely suspicious of $500/kg, which is about a third of today's cost.
Accepting everything they then do, forever, even when it's obviously nonsense, is what gets you called a "huge batshit crazy fanbase of boot lickers".
This "idea" is great party conversation. It's probably doing a great job of shoving around the Overton window, too (perhaps the real goal here?). It's, uh, not realistic, and anyone who is seriously "all in" on it (you're allowed to consider it and to dream, that's not the same as being all in) is not worth taking seriously no matter how much of the oxygen in the room they're using up.
the first booster landing after delivering a payload to orbit was quite something and made a serious stir in the industry.