[brudgers]

I’m wondering…what the engineering challenges would be

The standard engineering challenges: costs and benefits requiring engineering analysis of actual stakeholder requirements and general principles of life safety.

In this case electrical utilities, electrical equipment manufacturers, and end users are obvious stakeholders. Life safety is harder because current systems have made more than a century of dumb tax payments in the form of corpses and property loss…life safety practices come from experience not theory.

Finally, to me it looks like the low hanging fruit are being converted to DC systems that are compatible with our current infrastructure: laptops, electric cars, etc.