I actually googled before writing the comment (preposterous, I know; also, out of vouge, should've asked chatgpt) and the bacteria thing was the only thing I found, nothing macro scale, which made sense since it's easier to rebuild than to heal. Anything bigger than that would have to be healed and it's hard enough to fix mechanical bearings, can't imagine how to regrow or heal one even if it somehow grows. Maybe it's an issue with my imagination ;)
Good point about rebuilding vs. healing. We're kind of rediscovering it with economies of scale and price of labor making it much cheaper to replace things than to repair them.
I can imagine evolution creating macro-scale wheels that can be healed, and/or able to survive long enough before failing to be advantageous - after all, bones and teeth can hardly be healed if badly damaged, and yet they last long enough to stick around as core design elements.
This is why I mentioned roads. Whether or not evolution could iterate its way to macroscale wheels, it wouldn't, because they'd be useless without roads. Legs may be more complex overall, but they're an all-terrain solution that can be incrementally improved, and every improvement step grants improved survivability.
