VIA, as always, very well said, but I came away asking myself: What is new here? After all, White Elephants are the essence of the Kingdom's (Grandiose) Vision 2030 -- cf. https://www.vision2030.gov.sa/v2030/overview/
In other words, business as usual in the KSA. With one difference: KSA's ego may well be far larger than those of his predecessors, and his determination to build monuments to his own greatness much stronger. And, of course, MBS is still young, and so (in theory) he will have many more years to invest KSA funds' in his personal sandbox because he is the KSA.
So, yes, the mono-maniacal Monarch MBS will have huge cost over-runs that will have to eventually be paid for by oil consumers.
But I thought we knew that already?
And, of course, dollars spent on KSA's monuments to his own Royal Greatness do not increase oil output. Which we also knew already.