This is not a Japan problem. The only time a European system got sold outside Europe was Korea’s KTX, which is a dead ringer from the TGV. The Texas Central Railway was the closest we got to seeing a Japanese bullet train and that proposal is probably dead.

Europe’s rail density still promotes Intercity and Regional rail and that’s a business Alstom bought into by hook or crook. And they and SNCF, DB etc fight to keep that same graded rail for their bullet trains and intercity over maglev. This isn’t going to change, because speed changes stem from capacity, not technical preference. Europe doesn’t have the problems Japan has with capacity stemming from density.