I can't speak for the situation in Portual as I don't live there, but the problem that I witnessed in Vancouver is that the type of housing that developers start building starts shifting to be explicitly catered toward a pied-à-terre product for a foreign audience. Eg. Vancouver developer Westbank was literally opening up sales offices for their condos in major cities in Asia.
I wouldn't be surprised if similar things were happening in Lisbon.
So while you're absolutely right the problems can be solved by encouraging more housing construction, the solution is eroded when the developers themselves don't play along and aren't building a product that is relevant to locals.
After Vancouver added its various speculation taxes, Westbank closed its sales offices abroad and even went so far to go back to the city and have them go through a re-rezoning of projects already approved to change them from luxury condos to purpose built rentals.
I wouldn't be surprised if similar things were happening in Lisbon.
So while you're absolutely right the problems can be solved by encouraging more housing construction, the solution is eroded when the developers themselves don't play along and aren't building a product that is relevant to locals.
After Vancouver added its various speculation taxes, Westbank closed its sales offices abroad and even went so far to go back to the city and have them go through a re-rezoning of projects already approved to change them from luxury condos to purpose built rentals.