Are you also anti-shoe? I imagine all rubberized treads would do this to some degree. My guess is that temperature and speed matter.

I guess you could use clogs or geta or something.

The forces on car tires are much greater than on bike tires because cars are much heavier and go faster.

Look at the thickness and width of a car tire vs a bike tire and you'll be able to see how much more material is worn off into the environment during the life of the tire. It's magnitudes worse in the car and people are absolutely doing the environment a favour switching to alternative transport.

Yeah but then our oceans would be filled with sneaker dust instead of tire death and we’d be right back to square one!

My ENT office/Surgical center is across town. Are you suggesting that I walk for three hours with a sinus infection to an upcoming surgical appointment? And then walk home afterwards?