tourism can be so lucrative that it is actually profitable to force out normal people and completely reorient the economy away from all other productive activities. eventually large parts of the city will become totally stagnant, but this doesn't seem to stop tourists from coming. there's often a constituency of people who are really benefiting from tourism (property owners, tour operators, restaurants) and who form a powerful bloc opposed to any restrictions or taxes.
it really seems quite similar to an economy where natural resource profits drive everything, it's impossible to get any other industries off the ground or make enough money to live in any other way.
The reality of the matter is that what's happening in Barcelona ended up resembling more a colonization when tourism got combined with golden visas that allow rich foreigners and investment funds to scoop up local housing and the recent digital nomad wave. There are now more foreigners in the city center than locals and you are hard pressed to hear Spanish or Catalan being spoken around the place.
"I was born and raised in Barcelona, no longer live there however. I didn't remember how bad it was until I went to visit my family last summer. Me and some friends went to walk around the center and the girl that took our orders at a Pans&Company didn't even know Spanish or Catalan, only English. It was honestly quite depressing. She was surprised we didn't open the conversation with English."
https://www.reddit.com/r/askspain/comments/1833ub1/comment/k...