Agreed. Thing is, they already sell tires that pretty much never go flat (Cooper Discoverer S/T MAXX). You add enough plies and strength and as long as you maintain pressure, you're pretty much golden. On a car where you want a light tire, it's pretty tough to solve. For balancing, they could maybe have a reinforced bladder in the center (or maybe towards the sidewall?) that has a viscous fluid. Might counteract imbalance from snow, mud, dirt, etc.