Yeah but the alternative in antiquity wasn't "whatever squishy compound", it was wood, perhaps with a metal strap around it, like a carriage wheel.

Which is why in the early wooden “bikes” (you were sitting on a wooden bar and pushing with your legs) they made the bar “squishy” by adding some sort of saddle or some adapted spring dampers or sth.

It's interesting that wood is considered impractical for a bicycle... but somehow practical for a carriage?

Carriages used to have suspensions (made from some elastic whale bone I believe).

If someone would attempt to build a bicycle in a time of carriages with carriage wheels, I would then expect this person to also copy (at least in analogy) the suspension systems for carriages of that time, if not on the first try at least on the second...

Understood.

That's not really accurate. Docked bikeshare systems in US major cities use real pneumatic tires. Citibike in NYC, whatever Ford Bike in SF is called now, Capital Bikeshare in DC, and more.

It's just some of the cheap dockless purveyors that use non-pneumatic tires, and these companies have been dropping like flies. The docked bikeshares by contrast are still (slowly) expanding with their superior, but admittedly more expensive, bicycles.