I listened to Elon's interview on I think it was Dwarkesh (https://www.youtube.com/watch?v=BYXbuik3dgA) and it was way past just talking up his book for the IPO.

I so wanted it to be true but all his claims, including this mass driver, had numbers that were so outrageous that it was obvious he was just making it up as he went along. All the hard engineering issues were just hand-waved away and all the trivial issues with doing things back down on earth instead were magically insurmountable. This is a modern "Selling swampland in Florida" scam.