[necovek]

That's wrong: the problem is the rubber on the wheel (or feet in case of legs) being spent due to the traction and emission of rubber microparticles as it is.

[Loughla]

Yes sorry I wasn't clear enough. Rubber and chemicals from tires on the nice road surfaces. That's what that should have said.

But the legs are still a solution in search of a problem.

[necovek]

Sure, the original article is about a legged movement, and the entire thread is about microparticle (plastics/rubber) emission comparison between wheels and legs.