The Italians were the main force in Baroque and early Classical music. However, Romantic music, which began in the late 18th century, was almost entirely a German phenomenon, at least initially. Such composers as Brahms, Wagner, Mendelssohn, to some degree Mozart and Hyden, and of course Beethoven come to mind. What happened?
Well... I asked my self the same thing and came with my own explanation, so this is just a hypothesis: Let me start with a rhetoric question: ¿What does Vivaldi, Mozart, Cervantes (the writer), Monet, and Aristotle have in common? No? Well how about: what where the social conditions in the era that each of them lived in? Those where countries that had a economic surplus. You can think of it as (I don't recall who described this) utopia in which the lower classes worked and the higher would do arts. Arts in general can be considered a merchandise, a luxury one. Now, the centers of art usually coincide with economic centers, like Rembrandt in the Netherlands, or Rothko in the US (more in NY). So in order to have art movements, you need a rich society As for the specific case of music in the Renascence and a little posterior time: most of the time, musicians had a sponsor or patron, a noble man who would ask them to compose something for them. A clear example of this was Luigi Boccherini who's patrons where: Luis Antonio of Spain, Lucien Bonaparte, Friedrich Wilhelm all of Prussia
I hope this helps. And if I'm wrong, for someone to lead me in the right way