I would point out that Sweden is unique on that list, as although they do have a monarchy, the king hold no legal/political power, not even in a "symbolic" sense.
A potential explanation for the phenomena you've observed is that it's uncommon for new monarchies to be started in the 21st century, so the countries that still have monarchies are all countries that for the most part have had stable forms of government for many decades if not centuries.
Also there are plenty of poorer countries with monarchies: Jordan, Saudi Arabia, Morocco, North Korea, Thailand, Cambodia, Bhutan, Lesotho, Oman, Qatar, etc. (I'll admit it's a bit suspect to label North Korea as a monarchy).
> the king hold no legal/political power, not even in a "symbolic" sense.
That's not true. The royal family of Sweden have immunity from prosecution, fines etc.
And not just in theory - there are actual examples of royal family members escaping speeding tickets, investigation into hunting accidents, illegally using the secret service to raid the homes of people suspected of possessing potentially embarrassing photographs etc etc. (see eg https://www.dailymail.co.uk/femail/article-1326783/How-King-...)
They also enjoy diplomat status while traveling abroad etc etc.
Not to derail, but I think you're correct in labeling North Korea as a monarchy. It's hereditary. Veneration of current and past leadership is at a level that might have embarassed the Sun King. The internal palace conflicts are practically identical to what monarchies in the past used to endure. They even go as far as to have a variation of "divine right" justified by the Juche ideology.
A Crusader Kings mod that would focus on the internal & external struggles of a cloistered totalitarian regime, like North Korea, would be very interesting.
Not as poor countries, but as poorer countries than the ones the parent comment mentioned. The GDP per capita of Saudi Arabia is around $23k - approximately half of that of Sweden, the Netherlands, or the UK.
Qatar is absurdly rich, but the wealth is inequitably distributed (unusually so). Although the GDP per capita is ~60k, the median household income (and the median per-capita income) are considerably lower than the countries the parent comment mentioned.
> The GDP per capita of Saudi Arabia is around $23k - approximately half of that of Sweden
Why are you mentioning nominal GDP, not PPP which is $55 grand according to CIA (which is more than Sweden's and UK's and just a bit less than US's)? If they raise their taxes to the level of Sweden they will have larger nominal GDP although without any increase in the purchasing power.
A potential explanation for the phenomena you've observed is that it's uncommon for new monarchies to be started in the 21st century, so the countries that still have monarchies are all countries that for the most part have had stable forms of government for many decades if not centuries.
Also there are plenty of poorer countries with monarchies: Jordan, Saudi Arabia, Morocco, North Korea, Thailand, Cambodia, Bhutan, Lesotho, Oman, Qatar, etc. (I'll admit it's a bit suspect to label North Korea as a monarchy).