The article didn't name Saudi Arabia, and it explicitly stated that it's legal for the monarch of Swaziland to live lavishly:
"Mswati III, the absolute monarch of Eswatini (formerly Swaziland) lives like a king—and it’s legal."
"Mswati III, the absolute monarch of Eswatini (formerly Swaziland) lives like a king—and it’s legal."
As long as Kings are content with what they have today we leave them be. It may be outdated and unfair, but its stable and usually not too terrible for the people. The alternatives may not be much better either, especially in countries with high levels of corruption. There is a hope that all monarchies will eventually crumble and be replaced by something more representative now that the concept of divine right seems quaint and out of touch, but power tends to be self supporting so it will likely take a long time.