If only Saudi Aramco IPO'd they could have diversified with that capital, now it's the usual business plus some fantasy high tech 'planned city'. Was it all an ambitious failed dream?
Murdering dictatorships seem to have a problem letting go of control. So I'm saying yes, they had the wrong people advising them.
Ignoring the giant elephant that Saudi Arabia didn't even feign "don't be evil", in order to engage in global market capital. Not even temporarily during the IPO, they could have put on their good face to the western world.
Instead the top down crafting this IPO gave the "okay" to murder to WaPo journalist and create a global PR disaster because their feelings got hurt.
Yet as you mention they still need to diversify, eventually. I wonder how it all will turn out looking back in 5-10yrs.