My opinions:
The housing market has been stagnant since 2010 while at the same time interest rates have been low. The population might not have risen a lot since 2010 but the usual trends of moving to city centers, people leaving their parents house (which keep the same house), people wanting new/bigger houses than their parents are still pressures present.
This means there's a big pressure in demand for housing which is not being met by supply which increases the prices. My speculation is that foreign investment has a very low impact in the housing prices, but it's just my speculation. Even if it's a considerable impact, the fix is always to increase supply of houses so that prices drop and we also get foreign investment.
The evolution of new housing construction over the last years https://www.pordata.pt/en/Portugal/Completed+dwellings+in+ne...
The number of conventional family houses in Portugal https://www.pordata.pt/en/Portugal/Conventional+family+housi...
My opinions: The housing market has been stagnant since 2010 while at the same time interest rates have been low. The population might not have risen a lot since 2010 but the usual trends of moving to city centers, people leaving their parents house (which keep the same house), people wanting new/bigger houses than their parents are still pressures present.
This means there's a big pressure in demand for housing which is not being met by supply which increases the prices. My speculation is that foreign investment has a very low impact in the housing prices, but it's just my speculation. Even if it's a considerable impact, the fix is always to increase supply of houses so that prices drop and we also get foreign investment.