It isn't that recent. The ancient greeks lifted weights and ran for general health. We know the Olmecs played ball games and one imagines they observed the health effects of staying active. Boxing is at least 5k years old. There are 15k year old cave paintings of wrestling. The Maasai have intentionally practiced high jumping for ? centuries. One can imagine that early persistence hunters probably ran competitively, as their modern counterparts do. A lot of these activities had non-health purposes but it isn't a stretch to think people in the distant past associated activity with health.

It's being sedentary that's quite recent.

In my view, failing to experience training your body and seeing yourself improve is analogous to never finding love, never enjoying art, never enjoying learning. It's a part of the human experience we've evolved dedicated pathways to make us enjoy and opting out of that is a crying shame.

In the past most people would have exceeded 7,000 just living

Usually you worked until you were exhausted. or else, No?

Yes, hard physical work was the main form of "exercise" for most people.

Or you worked until you were told you were done for the day, and no sooner.

In pre modern times, being unhealthy was likely to kill you or starve you.