The availability of credit cards in Europe is no issue. It's just as easy as in the US to obtain a card.
The issue is the people. Germans are especially conservative. Paying with a plastic card instead of cash at retail is still being regarded as voodoo magic by many. And then paying with a plastic card on the even more magical interwebz is teh crazzzeeehhh
.
Seriously though, people here are extremely suspicious of anything non-tangible. It also took ages before online banking became somewhat popular and there are still many who won't do it for fear of hacks.
Also,
girocards are so popular over here that many don't see the need for an additional cash-free payment solution. Especially not one that costs an annual fee. Girocards are issued free by our banks. Credit cards require a fee.