This, plus the fact that the last 30 years have seen an increase of 0 in real term for wages, plus a government that has done nothing over the best economic years we had from 2014 to 2019, and massive unchecked immigration(that has already received negative notes from the EU as illegal), and you have the ingredients for a nice habitation disaster, which is what this is.
Oh, and no effort to create good public transportation to connect cities to make reasonable living outside Lisbon. Or even try to push job creation out of the Lisbon district. And this is all before we talk about all the governmental decisions that have done nothing but decimate the renting market.
Speculation has its hand, but it pales in comparison to good old fashioned mismanagement of the state.