Trans Atlantic airlines make their money from premium passengers.
Its a question of RASM vs CASM. These days a CASM of $0.10 will require a $600 R/T for a 3000mi trip just to break even if the plane was full. Not quite a cheap ticket.
In reality a Y class only airline would be charging more like $900-$1000 R/T w/o an F or B class to subsidize the back end of the plane.