Surely, there is just as much rotational inertia in all those thousands of wind turbines as in a few steam turbines?  In fact, as the specific output is MUCH lower(wind turbine works at just Pascals of deltaP, steam turbine at Bar of dP), there must be MORE inertia as a total in the system?  In that video, you are standing behind a MASSIVE couple of tonnes of rotating blades (which, ok, only do about 60rpm) but also right next to that blue generator, which is geared up and hence has a larger referenced inertia.