> 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.