Some countries have strong national libraries and centralized library systems.
That allows for a national library policy and central development planning. Germany, however, until the second half of the previous century showed a rather chequered map of numerous independent kingdoms, dukedoms, great dukedoms, and principalities. This explains also the polycentric library scene. True, the unificatio n of Germany led to major central achievements, like a union catalogue of the German libraries, union files of serials, a world catalogue of incunabula, and many others, most of them started and run by the Royal Library in Berlin, later the Prussian State Library. While a federative system has many advantages coordination is something difficult and time consuming to achieve.