> 1) electric cars acting as buffers. Particularly rarely-used vehicles could earn some side money for being used in a smart grid.

Bidirectional V2G systems only exist as demonstration projects now, and we'll need a bunch of time to ramp that up. It requires a lot of EVs, lots of grid updates all over the place, and for people to willingly participate at a meaningful scale. This won't be cheap and the grid we have now can't handle it.