If Catalonia does become independent, the people will soon be slaves in their own country. Catalonia will be controlled by Islamists that the leftists have welcomed in.
I keep hearing that Catalonia (relative) prosperity pays the tax bill for the rest of Spain. Perhaps true, but the picture changes when they have to raise an army, Navy & Airforce to protect their new borders. That’s on top of the socialist spending programs of their local government. Unless they can make themselves ‘Switzerland’(Spain controls that outcome) then they are in for a rough stretch, fighting or no.