@jefftk Practically speaking, running by default seems more difficult since in most situations where I could either run or walk, I find that I am encumbered by something like a backpack (which would bounce and be uncomfortable) or a cup of tea.
I also get the feeling that running is slightly more likely to lead to collisions, which is a bit hazardous for people around you.
We're no longer energy constrained (and in fact people would probably prefer to burn more calories), but our instincts and aversions are still tuned to efficiency.
¹I think this actually depends on walking speed, but you need to walk pretty briskly for walking to be less energy efficient per distance than running.
@zebrask if this were the only reason this would push strongly in favor of trying to overcome the aversion
@zebrask my backpack doesn't really bounce when I run (and I'm wearing it for probably a bit more than half my running). It's mostly a matter of adjusting it to fit snuggly. If it still bounced with a good adjustment I'd buckle the waist strap.
a Schelling point for those who seek one