Re what they do 'in other cultures', not long ago I was discussing this with an Indian friend who lives in Mumbai, but who we see every summer. I said how often we in the UK are berated for 'dumping' our elderly in care homes, when 'in other cultures' people look after their own. The pious beraters are nearly always politicians, or celebrities, who typically will have not a clue about what it's like to care with someone with dementia 24/7.
My Indian friend said it was rubbish. Her own very elderly mother - with dementia - was looked after in her own home many miles away, by two live in carers, such arrangements being considerably cheaper and easier to organise, as my friend pointed out, in India than in the UK. She also said that such arrangements were quite common among those who can afford it. For those who can't, there is probably little or no choice.
My dd worked for a while in Cambodia, where in a poor village she witnessed the care of an elderly grandmother with dementia. The woman, who was incontinent, was tied to a chair outside all day, to stop her either messing up the house, or wandering off and getting lost. At the end of the day she would be hosed off outside.
I suspect that this sort of thing is the reality for the poor in many countries.
As for care homes, I don't know anyone who has taken the care home decision without a very heavy heart - usually when relatives have done their best, but simply can no longer cope with the 24/7 care now needed - and by that I mean someone on hand all day, all night, 365 days a year.
My mother finally went into a care home after such care had become an urgent necessity. She was then 89, and lived to 97. The home, which was a specialist for dementia, was extremely good - cosy and homely, with excellent staff. All care homes are not grim - far from it.