There are multiple sources of Porto's gentrification. On an academic exchange in Cluj, Romania in 2018 I met a Portuguese economics prof from Porto. She was buying apts, renovating and renting them to long term tenants. She didn't have time for Airbnb. My Latvian stepdaughter is moving to Porto from Amsterdam with her French fiance. She's a fashion designer with her own e-commerce business and wants to be closer to her Portuguese textile suppliers. In Porto she'll get much more sun in the next lockdown with a much lower cost of living: 40% lower rent + a sunny terrace. When we visit them we'll be part of the problem.

Real estate reaches its highest and best use, one way or another. It's government's job to protect the vulnerable, but not to guarantee anyone an inherent right to a city center apt for 100-200 euros/month. NY's rent stablilization laws are one example of a workable compromise. But Porto is not an island with limited space to build.

When I lived in Portugal during the Carnation Revolution in the summer 1974, it was obvious the country's sleepy austerity-wracked economy would wake up. Airbnb is a late arrival to a process that began two generations ago. Since it can't be stopped, it's a question of how best to limit short term rentals so high demand areas' legacy residents are protected.