It would be interesting if they come up with an aircraft equipped with only J and Y+, where first 2 cabins are J and last 2 cabins Y+.
Y+ is very well priced. Good luck finding a seat on IST-LAX in June-September. if you find one, it's priced at ~3k$ return, which is a good price fro TK to make money. Of course, Y+ loads in Asia are not as high...