Agreed 100% that we need to decentralize.

To the extent that solar/wind/battery can power a microgrid without needing external power, the grid becomes less necessary - but we'll always need to move power from one place to another. Large hydro, for instance, tends not to be near the places where that energy is of most use.

At the same time, we need to make our grid more repairable, to minimize outage time.

Yes, EHV transformers are a critical weakness. If one fails, it could take months to replace, as they're large and heavy enough to present rail/road transportation and installation challenges (huuuuge crane) - and they're expensive enough that a utility is unlikely to have any number of spares on hand.

Fortunately, some folks at DHS have been on this for the last decade or so. One thing that's come out of DHS is the 'Recovery' EHV transformer, which can be installed in about a week. There's some clever engineering (3 single phase transformers rather than a single three phase unit, making each small enough to be transport-able over the road; each comes on a Schnabel-car-type base, which can become part of the flat-bed, and then becomes the foundation for the transformer, potentially making a heavy crane unnecessary; cooling-oil service that takes days rather then weeks).

All that said, I'd suggest Puerto Rico's grid as a decentralization 'lab'. We'd learn lessons that could be applied to the rest of our grid - and PR would come out of it with a more resilient grid (admittedly a low bar).

Disclaimer: I'm not a EE, just a software comms guy who got interested in grid cybersecurity.