I drive a Subaru Legacy (2015) and its CVT has a strong drag when your foot is off the pedal. I think this is just engine braking with the car having been programmed to not supply the engine with gas without the pedal being pushed above 20-ish mph. While it's nothing like an EV's full regen, it might be on par with some low regen settings in some EVs as I can slow down in traffic fairly quickly without touching the brakes. While I haven't driven a manual before, it seems that this behavior is identical to constant downshifting. With careful driving, I can avoid using the brakes until at very low speeds. Personally, I really enjoy it.
Going full one pedal with nothing other than friction brakes to slow the car down would most likely result in higher gas usage as people would end up using their brakes more frequently. Coasting would also be very difficult to perform and there would be no energy benefit to being slowed down beyond engine braking. It's not like you can regen gas after all, so it's just a waste. In a time where all automakers are trying to eke out every bit of fuel efficiency for as little money as possible the last thing they'd do is shoot themselves in the foot.