My grandparents are in their early to mid 80's, and at least one person in each couple has started to seriously decline. Both sets have End of Life directives, wills, trusts, instructions, even funeral instructions set up. When we get close to that point, both couples have planned fairly well, far in advance, and discussed with all of their children.
The problem is the decline, and pride. The healthier person in each couple still has their full pride and dignity, and is resistant to change. On one side, the healthy person IMO has lost the ability to step back and see how much their situation has changed over the last 4 years, and what kind of steps they really need to take. They are very very resistant to a CCRC because the sick spouse said he'd rather die than "go into a home". Well, they're one accident away from that happening, and she's too afraid to spend money on in-home care. To the person who talked about multiple generations living together - that would be helpful, but it still doesn't solve the pride problem, if the older generation doesn't want to listen to the younger when they bring up valid concerns. I think that is the start of a lot of issues for people on this board. That and boundary setting.
Both sets of my grandparents have had strong friend networks, but now are losing those friends to illness and death, and can't count on those friends in times of need at this point. So they turn to their kids more and more to meet little needs and big needs (like call the computer company, this is too complicated for me anymore to handle my bill paying please) and for social interaction.
And +1 to the people pointing out that most are living longer, and after the point where a few decades ago they would have died. One of my grandparents would have been dead by now* back when he was born, probably through the 70's. My grandma always talks about her grandma is her role model and was a strong German woman who took care of her husband through the end. Well, true, but (my) grandma can't possibly be held to the same standard, because the end line has moved.
*which is morbid, but the truth