The Catalan people can govern themselves better without Spain’s help. Catalonia already has its central government based in Barcelona, with the necessary parliament buildings and its police force, schools, and health care system located there. According to a government researched white paper released by the Catalan regional government, much of the infrastructure, legal framework, and bureaucracy needed to secede are already present under the 2006 Statue of Autonomy. Although new systems are needed, Catalonia already has most of the infrastructure needed for any interim period that would follow a formal declaration of independence. In 2013, CATN, an advisory council made up of legal and technical experts, produced detailed advice to ensure the preparation of Catalonia for any split. The economic gain from no longer losing 8% of its GDP to the Spanish government would be more than enough to improve infrastructure and services. With the extra money in tax revenues that independence would create, existing infrastructure could also drastically improve, and would eradicate the issues that stem from a bureaucratic government in Madrid. Spain has been actively attempting to recentralize and has underspent on infrastructure in Catalonia. Catalonia is already semi-autonomous and has most of the necessary infrastructure needed to be an independent nation. A break from Spain will only improve the quality of this infrastructure.
Almost all calculations on the viability of Catalonian independence discount the possibility of a drop in GDP caused by the transition. Catalan nationalists cherry-pick economists who agree with them, but some financial institutions have estimated Catalonia could lose up to 37 billion euros if they break with Spain. Catalan separatists have not considered the debt they would have to pay back to Spain, the cost of a Spain-Catalan border on export revenue, and whether they would become a member of the EU. The central government has listened to Catalonia's complaints about the deficit in infrastructure spending and agreed to do more to ratify the problem. For example, Spain promised an extra 4 billion euros to fund the Catalan rail network. Claims that Catalonia will run their institutions better than Madrid because Madrid has recentralized local government are false. Although the Spanish government has interfered in the region, Spain is still one of the most decentralized countries globally, according to the Organization for Economic Co-operation and Development.  Catalonia already runs itself. A bid for independence is both expensive and unnecessary. Complaints about infrastructure spending have been heard and addressed, despite secessionist rhetoric.
[P1] Catalonia is already largely autonomous and has many of the institutions it needs to be independent already. [P2] Catalonia will no longer lose tax revenue supporting the rest of Spain, which will provide extra funds for infrastructure and services. [C] Catalonia can support itself better as an independent state.
Rejecting the premises
[P2] Catalan separatists have underestimated the cost of independence.