I'd much rather have shitty care as an elderly person and leave my kids money etc, them living in a more luxurious care home
All depends what you mean by this. Having decent basic care can prevent pressure sores, dehydration, cognitive decline, medication errors etc. etc. - all of which are expensive to correct. You might have decent basic care in a home with no amenities, outings, dismal views, basic but clean rooms etc. Your children wouldn't want you permanently ill because of poor care.
Or, you might have very poor care, live in fear of assault or bullying by staff/other residents, constantly pick up infections, be back and forth to local hospitals, always falling etc. etc. Your children wouldn't want you mistreated.
And, beyond that, there are the size of the rooms, views, activities, staff to resident ratio etc. etc.
And, that's before you get into the costs of somewhere that will accept some degree of incontinence or nursing needs.
Adequate care that is appropriately monitored and kept up to a decent standard costs considerably more money than is feasible for most people. The UK is managing now because family members are doing it (despite what people think) - what it's going to like as our demographics change and our current carers age out of being able to cover the number of people who need it?