The G1000 in the USA does have a proper ADF, but you must purchase the add-on. It is not an issue of USA vs Europe, itīs an issue of if the owner wants to spend the extra $$$ or to have an ADF in their plane. Most G1000 owners in the US donīt buy the ADF because it adds to the pricetag and they feel that with GPS and VORs, that an ADF is an unnecessary expense. My flying school in the US had a G1000 equipped plane, but no ADF, when I asked why, they said that the owner (the owner of the plane was actually one of the students who leased it back to the school) did not want to spend the extra money on an ADF. There was even one student at my school who refused to learn NDBs to the point that he only flew the G1000. Since NDBs are still used extensively throughout Europe, I imagine that the ADF is readily found on European G1000 cockpits.
NDBs exist in the US mainly for training purposes and are not usually used for primary navigation unless someone is trying to stay current or wants the practice.