[iSnow]

This is being done and it's called synthetic inertia. Just with capacitors and batteries instead of spinning motors.

[adrianN]

To my knowledge Siemens is currently making a lot of money by adding spinning inertia to the grid because that is easier than getting the response time/power out of electronics.

[iSnow]

I am not in that field, just a curious citizen, but Siemens seems to offer synthetic inertia gear too: https://www.siemens-energy.com/global/en/home/products-servi...