I sure hope spatial audio won't be the only way music will be delivered in the future. It'd be a complete nightmare for people like me who has severely impaired hearing on one ear.
Wouldn't that also apply to mono v stereo? I would guess that if you had one earphone in, they would fallback to a mono/stereo mix. It kinda works like that currently with AirPods. If you take out one, instead of only getting one channel through the remaining AirPod, you get both channels diverted to the one AirPod.