Modern Man isn’t any more lazy than our hunter gathering ancestors, we are just enabled in a way they weren’t.
Humans evolved from hunter gatherers, which didn’t routinely expend energy they didn’t have to for “no good reason”. They got their exercise from all the work they did to simply subsist and survive.
🔑 Humans have evolved a strong urge to avoid unnecessary caloric burn, maybe more so than most other animals.
The great apes are lazier than humans. The modern human is lazier than our hunter gathering ancestors, but not by a ton (see: Sitting), and most other animals are less lazy. This is defining laziness as the proportion of calories burned from typical daily activity (TDEE) to those burned at a state of rest (BMR).