Having taken care of some elderly, and watched others pass, my impression that living forever appeals more to the young than the old. Some of it may be their bodies breaking down, some of it may be losing old friends and loves, but most of the folks 75+ seem to be ready when the time comes. Certainly more ready than their kids.
But still... To quote the Rolling Stones, "What a drag it is getting old."
However, if they have the body and mental acuity of a 25 year old at 75+ and so do their friends, they might not be as ready for it. And not need people to take care of them.
All of your argument is null and void if you take out the "dying" part.
It's like saying "Nobody goes 100 miles in a day because they can't walk that far, so nobody is going to want to ever have a car/bike/airplane" also walking that far tears up your feet so a car is silly."
My stepfather passed away two weeks ago, and my mother is worried that she'll live as long as the women in her line; roughly 90+. To her, that's a nightmare of infirmity and worry. Will she have enough money? Will she be independent, or have to rely more on caregivers? She's only 80, so she's got a good decade or more to think about these things.
I think if she wasn't alone and in declining health, she'd be glad to live longer.
But still... To quote the Rolling Stones, "What a drag it is getting old."