[sammyg2]

With current technology reducing rolling resistance usually means giving up traction, and no one wants to sell a tire or drive a car that is less safe just to get a few more MPG. Well almost no one, there are some huggers out there that are allergic to logic.

Tire manufacturers have been dumping a butt load of R&D money into developing some "revolutionary" tire for decades.
The only one that showed any promise was the air-less tire, but cost is prohibitive along with some other performance give-aways.
Tweaking materials and tread design has helped but I'm a bit sketical we'll see anything as revolutionary as the radial tire anytime soon.

When they went from bias ply to radial the traction and mileage improved.