> With a bunch of AC microgrids joined by a DC major grid, you can completely sidestep that problem.

Not necessarily. Big local consumers will be large relative to the microgrid, which will not have a lot inertia. This is one of the things that you really notice when you go 'off grid', your grid is essentially your house and whatever else you decide to power from it and unless there are a couple of beefy motors already running starting a new one has a high likelihood of tripping the inverter, even a very beefy one. Start-up currents for larger consumers can be really high and you need a lot of inertia in your grid to overcome that.

> Start-up currents for larger consumers can be really high and you need a lot of inertia in your grid to overcome that.

This is true of an AC grid as well. Big inductive loads will often have to buy special equipment before hooking up to the grid because of their impact. It'd be the same with a DC first grid. To overcome a large startup current they'd likely need to buy a bunch of capacitors. Which, funnily, is exactly what they'd have to do to run on straight AC.