> Needless to say, they are not the most efficient and are even less prone for innovation.

I think the main problem is that both co-ops and Sparkassen are very decentralized, you're looking at literally thousands of tiny and not-so-tiny-but-hardly-big banks that are all completely independant. That makes innovation very slow - of course they have pooled resources to have a somewhat centralized IT infrastructure, but the power to decide on innovations is ultimately still with the thousands of member banks.