Problem is that it's in areas where people don't want to live. In the areas people want to live, the problem is the opposite, there isn't nearly enough housing, so you end up with some of the highest population densities in EU (#2 and #3 are both in Spain at https://en.wikipedia.org/wiki/List_of_European_Union_cities_... in "density per km2" for example, 50% of top 10 on that list is in Spain!) and prices keep going up.
Add in that salaries are pretty low so cost of living is subsequently low, so you end up with a ton of "expats" and other fun folks like "foreign investors" who purchase up all the livable/rentable properties with their "higher value" money, because everything is so cheap for them.
Owners realize this, and while the government is (now at least) trying to put a stop to all of this with limiting rent increases and more, owners still try to take advantage of it as much as they can.
Personally, I think we need to temporarily put a complete halt to non-residents buying any sort of properties or even land here, at least for a short period of time so the people who actually live and work here can recover from the situation.
For the average person with a normal job here and not working for foreign companies with a higher salary, it's short of impossible to be able to afford to eventually buy a house.