Like it or not it is fairly easy for top european teams and majority of EPL teams to take players from the likes of Celta.
None of them are showing any interest in paying 15-20m for Fontas and for good reason. You are way off by how highly you seem to rate him in a way no one else does.
Nowhere near the Spanish squad or near to a big money move. He is bang average.
Just watch some Celta games and judge for yourself then. There is a reason Celta finished 8th this season. And Fontas has been a huge part of that. Of course, you have no idea how close he is to the Spanish squad. Fontas is 25 so that puts off alot of buyers who prefer younger ones, but I havent heard any La Liga pundits who dont agree that he has been one of the most consistent CBs in La Liga over the last couple of seasons.