Everything Catalonian authorities boast is created while being in the united country, Spain. All other Spanish regions are not only recipients of money made of Catalonian taxes but also the nearest market for Catalonian goods.
All this mess strongly reminds me some rhetorics of local bosses in USSR republics before the dissolve of Soviet Union. "We feed all the Union! We are robbed by central government! Let us be independent country and we'll start living like in heaven and all our problems will disappear!". Yes, that local bosses who became the leaders of the countries got a better life. But I can't say the same about all other people living there. The same may happen in Catalonia. Very unlikely that it will retain EU membership and borderless trade with Spain.