When i first read on this a few months back, the issue was with leviathan cruise liners depositing two or three thousand tourists at a time, and with 5 cruise liners at once pulling in, it's a tidal wave of tourists all in one go. Similar to the Venice problem that's been in the news recently. I was in Rhodes town a few years ago, and three cruise liners had pulled in, and you could hardly move in the town, the streets were rammed.
The property prices going beyond the pocket of locals is a problem which goes way beyond Spain. This is an issue related to wealth and being able to afford second holiday homes. Certain wonderful tourist locations in Devon and Cornwall have prohibited anyone but locals from buying houses in the area. Similar with the Lake District. This to allow local people to be able to afford to live where they were born, without any local house coming on the market being hoovered up by "out of town" money looking for holiday homes and holiday rental investments.
I've stayed in some lovely places in the UK, and if you talk to locals at any length, they nearly all complain that house prices are rising way beyond local people being able to afford due to demand for second holiday homes, and that in the winter months, the place is question is nigh on dead, with all the holiday properties lying empty.