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I’ve read the article multiple times, just to be sure, and this seems to be correct. What are we missing?

From the article:

> The M32 system is a 5,000 kg, four-hour Kinetic Energy Storage System (KESS) flywheel technology. It can store 32 kWh of energy in a 2 ton steel rotor

32kWh of energy is 32kW for one hour, which is about the same energy as half a Model 3 battery.

The allure must be the lack of degradation, giving good long term cost (chunks of steel are cheap).

Could someone chime in?

I think latency is where they truly shine, should be near instantaneously available, as opposed to generators or some batteries. So 32 kWh yes, but the hour part is more like a few minutes, at which point the Wattage can be a lot higher, and thus a decent bridging solution between grid and backup for somewhat large installations.

The article says that multiple wheels can be stacked in the same installation, to increase capacity.

Sure, but with something around one per 16 houses, that's a massive (tehe) installation.

The average American house has around 5000 kg of cars, so it doesn't seem that infeasible.

Average house where? Here in my European country the average is more like 10kWh per day.