The reason that housing is increasing in cost is because of a market failure where politics is used to create housing scarcity, called "economic rents." In this case, the use of politics to create zoning laws that place artificial restrictions on housing density. As in any form of "economic rents", this benefits a special interest group -- in this case the landlords over the general population of rents and buyers of…
The zoning story is pretty much bullshit and is told by developers that want to replace the buildings with even lower density, shittier but still pricier buildings. The Eixample district in Catalonia has one of the highest population densities in the western world without high-rises: https://en.wikipedia.org/wiki/Eixample Its population density is higher than the one in Manhattan and probably also any parts of the ot…
I lack the experience to comment on the situation that you mention relating to Catalan.