difference between xbox bc and ps now:
xbox bc is trying to sell a new hardware with old games to an already existing audience because of lack of interesting new exclusive software.
ps now is trying to sell old, and i'm pretty sure sometimes in the future even new, software to an existing and a completely new audience (those who don't play console games) by making the playstation game catalog accessible on every entertainment hardware (consoles, phones, tablets, tvs, pcs,...).
two totally different things. not comparable.