Batteries are sweeping stability markets wherever they are set up. They're simply cheaper and better at it.

I'm not sure this is true in the UK at least, which may be because the grid operator is conservative / cautious https://www.energy-storage.news/uk-grid-forming-batteries-mi...

No, these are two different things. One is stability market, where batteries are now king, the other is physics of fault ride-through, where actual physical inertia is a real neccessity, at least for the time being. That is why synchronous condensers are installed.

Every major renewable grid has installed additional intertia to avoid blackouts.

No, batteries do that better too.

Variously called "synthetic inertia", "virtual inertia" or "grid-forming inverters".

Some people treat the spinning metal like vinyl records and think you can't get that "warmth" with the new tech but on objective measures, including cost, they win.

People install them because they were the old tech for this, and there's lead times and caution, it's just slowly changing legacy not something batteries can't physically do better.

Ah, that's nice to hear. This also means we won't have to have another type of hardware on grid, since the batteries can make this work.