The auto demolition has been suspended since Oct 2018, meaning all evictions for unattended houses stopped until recently (patch 4.57). Before then with the new one house/fc per account and timers on plots seemed to make things a bit better. I know on my server I could go to the aetheryte and see a few plots available for purchase.

That being said, before this housing was 10x worse. Try researching the ffxiv history of housing. When housing was first introduced, the prices were so astronomical that there were empty plots everywhere for a long time, nobody could buy them. Then they made them more affordable and plots were swooped up. Some single players with multiple houses to try to profit from the influx of buyers. RMT too had to stick their grubby hands in on this profitable venture that SE created from the start.

And now here we are and the auto demolition was finally put back in place two days ago, which in turn started freeing up a few plots. The players who waited through the long suspension of auto demo then piled on top of one another at what few plots became available. The kicking, screaming and frustration begins all over again. Buying plots is terrible due to supply and demand, but it did improve there for a time. I think SE's timing on removing the auto demo contributed to the frustration of buying plots. Right in the middle of server splits and transfers.