CRS is not that expensive on its own, but the ISS won't be around for much longer and it does cost a lot to maintain a crewed presence. In other words, Europe would be spending a lot on hiring Dragons/Starliners for crew plus the cost to orbit a new station, whatever that would look like, just in order to necessitate the need for a European CRS in the first place.

NASA seems to be going all in on commercial station(s). How that will work exactly is a bit of a mystery but there seems to be at least three (Axiom, Orbital Reef and Starlab) that seem fairly serious and are all getting some NASA funding. Mostly looks like private investment though. Looks like Airbus is a partner on Starlab so perhaps that is the one angling for ESA patronage the most. If that is the case, ESA wouldn't have control over the services contract since it would be commercially operated.

Its all interesting stuff but its still pretty early