This worked extremely well for my Dad's parents.We are thinking of moving to a facility when we qualify at 60. In Australia our facilities have 3 levels of care. First is independent living which would allow us to have an apartment or villa. When things start to go downhill we would get assisted living - stay in the same residence and they would come and provide required assistance. Last stage is nursing home where you are lying on a bed in a private room in the nursing home waiting for the end to come.
The local geriatric care consultant I've talked with added that the best facilities include a "memory care" unit for Alzheimer's patients who try to wander. There's also extra staff and cognitive therapy.
I don't know if it's like this worldwide, but here some facilities are putting considerable effort into physically separating the three levels from each other (separate entrances, separate hours for shared areas) so that residents don't unexpectedly come face-to-face with their future. Apparently some of the potential residents are a bit squeamish about this. Of course the facility welcomes volunteers from their independent-living residents, too, but they try to accommodate everyone's desires.