I don't only blame the models but the "market" and culture. The fact is that Germans hardly do anything beyond their social circle. When they do it is usually because a strong spur that is more than often related to money.
Using the TFP (people modeling for photographers in exchange of pictures) groups in social medias such as Facebook, as example, after five years in many communities of this kind I only found one model, and this model only agreed to pose to my photographs because I have complained in the community about no one willing to model (meaning that she did it for sympathy). While in Ireland, despite I joined one TFP group most of my models I found by talking to people, placing notices on walls and newspapers, things that in Germany does not work at all unless you offer a good money.
In the TFP group there was models and photographers telling that they often work with each other through the community, but after talking in person with many photographers I founded out that in TFP communities models and photographer only work with those who them already previously know (friend circle).
The conclusion is that in order to pursuit models for your project, if you don't have model in your friend circle the only way to have a prolific photography activity with models is offering money. A lot of money.
I have the impression that the close social circle culture is due to a kind of cynicism, meaning not trusting others enough, which we feel more clearly in is mall towns in South Germany like Freiburg where people always staring at each other in the streets, with the judgmental look as well as afraid of being judged the same. And in a culture influenced by cynicism there is no free enterprise since deals depend on mutual trust and risk (they trust paper, over documenting everything to have prove in case of deal conflict). Reason why in countries like Ireland people are willing to be spontaneous, experiment activities outside their circles and as consequence become more prolific because there are mutual trust among each other. Paper? No one care about it in Ireland, people trust each other word and the photography itself as document.
In Germany there are many photographers loaded willing to spend money on models, and the great majority of them are happy on have just a beautiful face or naked body to photograph, meaning that models doesn't have to even try to model or develop skills as models. Just to show their faces and do some bad over posing, charging the same and some times more than actually professional agency models. And photographers with money pay it anyway because is the only way to keep practicing, creating and developing your skills when there is rare models willing to go beyond their social circle for TFP.
This is terrible not only because of lack of skilled models and lack of wiliness to join creative projects for the creative sake, but also because we see all these modelling and photograph communities loaded with beautiful model's face but poor modelling quality photos.
I see that Germans have the tendency to be more technical, with their attention and preference on the light quality, image sharpness and contrast, and so. But Germans seems to also have the tendency to over do things which make the over technically aspect of the photograph looking like they over tried it. The same to models trying to show their modeling attitude overdoing it. And this over focus on the technical seem to lack on the pure flow and moment contact with the creative artistic work, because the money involvement makes everything too commercial and too serious and less spontaneous and less artistic.
Looking back, the rare models that I found who was not from my friend circle have one thing in common: they are dancers and sometimes the alternative kind of person. Dancers not only are more willing to join project for the creative sake but also, the ones who charge accept a more reasonable rate. On top of that dancers have much more skills as model because they have a better notion of body composition and sense of direction from the photographer.
I suppose that dancing is a more open social activity because you end up get in contact with many people outside the actual social circle. I am not sure though, it could be only the characteristic of alternative people. But I see they are more open to outside friend circle activities and people, and this contact to a broader world makes them more realistic about their rates, skills and look.
Just my perspective (which may be one among many).