How common are fold-up vs "standard" sinks in wet baths?

fj12ryder wrote:
I think a foldup sink would be most common in the low-wall popup campers. TBH I've not seen one in years.

I’m not super versed in the common differences between them, but what about motorhomes rather than towed campers? Do the self-propelled “vehicle” RVs (motorhomes and the like, not sure if there’s other terms for them) not usually have fold-ups for bathroom sinks compared to smaller, towed camper spaces?