I think that one of the big problems for full beds is that Pax have to be sitting in a seat for departure/landing. This doubles the amount of space for each pax and thus the cost. If they provided beds, they would not want to provide them one-for-one for First/Upper pax and so there would have to be a lottery for them on check-in. On one rotation there would not be enough for demand and on the next, half of them would be empty. The current trend for multi-function beds that alter to many angles is probably the best compromise.