It may be desirable in all cases, but to attain peak physical condition would require far more effort of you than would be worth it for most of us in terms of time and money invested for minimal extra day-to-day benefits.

E.g. I lift weights. I'm stronger than 95% or so of people around. It's been a decade long commitment of 3-5 hours a week of exercise. Lets say 4 weeks for 50 weeks a year on average. In addition comes meal planning and a substantial additional cost in supplements. Lets say it cost me $1k/year extra (almost certainly an underestimate). That's $10k+interest excluding things like the gym membership which would add up to almost as much, and about 2000 hours of time investment over a decade. I'll need to continue to invest about as much to maintain it over the next several decades to maintain the maximum viable strength for my age as I get older.

I doubt I've got 99th-percentile health. I have no idea how many additional hours I would need to get there by e.g. improving my endurance, tweaking my diet, improving my flexibility, reducing my stress, increasing my sleep and many more. That time investment starts to add up, and quickly take away from your ability to actually live life.

It's quite amusing when you complain over unsubstantiated and anecdotal data points when you don't even try to offer up anything at all yourself.

We probably don't know what 99th-percentile health is. But we do know that e.g. a variety of indicators of physical fitness affects a long list of lifestyle related illnesses. As does diet.

While narrowing down "99th-percentile" health precisely would be hard, it is clear that for a number of these indicators, for someone to even reach 95th-percentile or even 90th-percentile is going to involve more effort than they will consider worthwhile.

Perhaps they can achieve 99th-percentile health through some other combination of more moderate effort, but it seems reasonable to question your flippant rhetorical question of why someone would settle for 85th-percentile health on this basis:

Because it's hard.

That's what my argument boiled down to, with some examples as to why I believe it is hard. You've not given any counter arguments of any substance.

My "unsubstantiated and anecdotal data points" are not evidence, but it beats "nothing" when it comes to providing a starting point for discussing what 99th-percentile health is, and why it may (or may not) be hard any day.

I guess I'm just not sure that 3-5 hours of work a week (that's assuming that's the minimum required; I don't know if that is true or not) is all that much effort.

Eating fully nutritious food should just be a given.