I'm not bothered by Joe Average. No-one has a moral duty to become strong, fit, or buff-looking. (They do have a duty to be healthy, but that's a lot easier to do.)
I'm just pointing out that putting an extra 1kg on their squat is not a thing the typical person worries about. When we're talking about physiological limits to our performance, not only is it true that you or I are far from having to worry about those limits, but "Joe Average" isn't coming even within shouting distance of them.
Whenever someone quotes Casey Butt's or Lyle McDonald's work, there's always a howl of protest from a bunch of 60kg scrawny teenagers or 110kg fat guys about how this won't be a limit for them, honest, they'll bust through these limits with hard work and UberAnabolicMassGainer6000. And it's ridiculous, because they're so far under the limits today. It'd be like me saying I was going to bust through the 300kg bench press barrier when I barely do an 85kg bench press. Nice to have a long-term goal, but let's have some realistic short-term goals in the meantime. Let's see me do 100kg, 130kg, and so on first.
It's important to keep in mind just where you are, or where most of us are. And that is far, far below any physiological limits we have. So far below that those physiological limits are basically irrelevant. Much more relevant is the limit of how often we can be bothered getting off our arses to lift or run, how much good food we're willing to eat, and so on.