European Wars (such as the Netherlands war), collapsing internal industries resulting in a shift from exporter to importer, internal revolts like the Moricos Re

European Wars (such as the Netherlands war), collapsing internal industries resulting in a shift from exporter to importer, internal revolts like the Moricos Revolt, and lack of investment in industry, and Phillip's penchant for foolish and grandiose national project bankrupted Spain. Throw in a couple of plagues and failed crops as salt in the wounds and that's a wrap. The massive influx of bouillon and spoils from the Americas were the only thing that kept up the facade for any length of time. Spain's problems were entirely domestic. At least according to the history books I've read.