MBS may have splurged on himself ever since he came to power, but he actually put good people in decision making posts in the public sector, particularly finance, foreign affairs, oil ministry and ministry of industry.
And in the years since he has been running the show, he did not initiate any projects that were destined to the White elephant hall of fame. The Jeddah tower pre-dated his ascension to power. Even Neom started out as a really good idea.
The pivot to ludicrous level ambition is more recent. I don't know what happened. I can only guess that a year of $100+ Brent fuelled this break with discipline.