Yemen is not one country, but rather in a similar situation to Syria. One Yemeni government is supported by Saudi Arabia while the Houthis, who shot the missiles and are unrecognized, are supported by Iran
Of course, the supply of housing is not the only factor. Another is the investors buying up property which you mentioned, and the fact that people selling houses just know that they can get away with high pricing. Both of these need to be fixed, in addition to the low supply of housing.
Do you think the Russian oligarchs, who by the way pen a FAR larger portion of the Russian economy than their American counterparts, appeared from nowhere after the collapse of the Soviet Union? The Soviets had an extremely wealthy and influential elite
The love for landlords meme, it was a subreddit where people pretended to be particularly shitty landlords