It should be a huge red flag that one "nice" country has more than 20% of it's population living abroad: https://poligrafo.sapo.pt/fact-check/cotrim-de-figueiredo-po... (you might want to use Google Translate on this one).
I also saw some comments blaming the tourism for this "bubble" bursting. The portuguese can't complain about tourism since it's a huge part of our PIB.