My understanding is that unique historical, cultural, and even geographical factors have led to this outcome for Oman. I would encourage you to read up on the history of the country to understand the nuance here and not paint with such a broad brush.
Everyone has a unique "..." and a nuance here and a nuance there.
UAE has a unique yada yada and also ended up with a surprisingly remarkably free economic index despite being a theocratic monarchy.
As did the monarchy Lichtenstein, British controlled Hong Kong, and the one-party state of Singapore (technically democratic, in practice it functions like a recallable monarchy).
Also of note the three richest countries by GDP PPP per capita are Monaco (hybrid monarchy with monarchist veto powers), Lichtenstein (hybrid monarchy with monarchist veto powers), Singapore (single party state).
I'll yield that it isn't a pure one party state. There is some room for difference of opinion whether you want to characterize it as one or not.
But let's not play the bullshit and borderline xenophobic, ad-hominem attack that it's just "outsiders" who "just don't understand." Or try and distinguish that it's people 'imposing their worldview' (something every human does no matter what they are arguing).
But don't take my word for it. Read what Lee Kuan Yew had to say himself[0]:
Ah yes, good ol LKY, the outsider who just doesn't understand Singapore, and with such a non-Singaporean 'viewpoint' that he had quite popular support (even if you want to argue it is a minority, it was widespread enough as to be valid enough to be considered one valid and widespread Singaporean point of view). Calling it not a two or multi-party system, leaving quite obviously his assertion is that it's a one-party system.This and other points, documented by Yeo Lay Hwee (Senior Fellow, Singapore Institute of International Affairs) , who even if she flip flops between suggesting Singapore is a one-party state, lists quite a few reasons why it is a reasoned viewpoint from an understood observer [1].
[0] https://eresources.nlb.gov.sg/newspapers/digitised/article/s...
[1] https://library.fes.de/pdf-files/iez/01361007.pdf
I'm not sure what the conclusion is from this other than that the wealthy love having an autocratic tax haven microstate to park the money they earned from liberal democracies in.
This is true, but these countries aren't doing it for the benefit of foreigners, they're doing it for the benefit of themselves.
The UAE is not theocratic. Yes, Islam is the official religion but there is freedom of religion.