That's a really valid point - the people who are actually providing all this care are paid a pittance. And in the case of unpaid relatives doing caring, a tiny allowance that in no way makes up for the salaries and pension contributions they might otherwise be making. Both sets of people (and let's face it, they're mostly women) will end up impoverished.
I honestly think some form of inheritance tax is the only sensible way to go. We've been through this situation twice now, all of my gran's assets including the house went on care home fees - fair enough, my mum wasn't well enough to look after her safely and I was deep in the baby and toddler stage at that point, so care had to be paid for to keep her safe and well looked after. My father in law died last year and although he was paying for his own care, he only lived a few weeks after moving in to the care home so his assets were intact.
Both of them had great care, but surely it would be fairer to everyone (including those expecting to inherit) if that cost was shared across the population rather than being the luck of the draw? In the case of people with disabled dependants, as a PP mentioned up thread, there would have to be some kind of trust available to them to protect money needed for their care, but even there, if social care was able to be properly funded and staffed, the costs to the individual should be less anyway.