The rest of Spain is a stuffhole and Barcelona has a booming economy. If anything an independent Catalonia would probably have more of an economic presence in Europe than Spain.
'booming economy' their GDP per capita isn't even in the top three of spains provinces and their economic growth has stagnated to the point where it's declining.
You get it really wrong when you say "they have nothing of real value to offer the world in terms of raw materials or service based."
Except they don't and you know it. Thats why you never address this later on in your post.
They would absolutely be better off without Spain, and Spain knows that. That's why the elites in the country don't want it to leave,
Entirely wrong. They don't want Catalonia to leave because they fear it would have a domino effect causing the Basque country and other regions to want independence. No country wants to be balkanized.
because without Catalonia's economy the country's going to be further in debt. If Catalonia became independent it's not like they would cut themselves off from the rest of the world.
Catalonia would be cut off from their largest potential trading partner which WOULD be spain. And as of right now if the EU wouldn't let them in (which since they don't support their independence, they wouldn't) Catalonia would be nearly completely isolated economically and would collapse.