> And they provide grid stability by having rotating masses on the grid, and thus combine pretty nicely with small to medium amounts of intermittent renewals that can provide some of the peak power.

We already have grids operating without traditional baseload. This is a 2015 talking point.

See for example South Australia keeping either 40 MWe or 80 MWe fossil gas in standby (I would presume this is the lowest possible hot standby power level for said plants). They are aiming to phase this out in the near future as storage comes online.

https://explore.openelectricity.org.au/energy/sa1/?range=7d&...

Inertia is trivially solved in 2025. Either through grid forming inverters which today are available off-the-shelf or the old boring solution of synchronous condensers like the Baltic states used to have enough grid strength to decouple from the Russian grid.

https://spectrum.ieee.org/baltic-power-grid