A slight change in materials science to make commutators easier
DC can do everything AC can do, just that DC needs a rotating machine for voltage conversion, where AC can use a no-moving-parts transformer.
In DC, that is irritating and expensive because rotating DC machines need commutators, which is a cylinder of copper bars brushed by carbon brushes. From time to time, the surface needs be smoothed, brushes changed, and mica insulators between commutator bars notched down a bit so they are lower than the copper. (Otherwise abrasive mica will tear up the brushes pretty fast). Carbon brush dust must also be removed from the mica notches to keep it from shorting.
This is all a big pain.
Now imagine a slightly semiconducting teflon coating which could be painted on top of the copper bars. Where it is thick (between bars) its resistance is very high. Where it is thin (over copper bars) its resistance is nil. It's laid in a continuous surface - no mica gaps. This, coupled with a magic brush material, means the DC commutator just doesn't wear. Bearings are well mastered, so the upshot is that a rotating machine has about the same reliability as a transformer.
They even put the bigger ones in sealed cylinders and pull vacuum on them to eliminate windage loss and increase insulation strength.
Voltage conversion can now be easily handled with an M-G set (if you need isolation) or a dynamotor (if you don't).
Now, why put up with the drawbacks of AC (e.g. Having to synchronize grids)? If someone really really wants AC, an M-A set can do that.
The railroads are heavily involved
Until rectifiers came along, railroads preferred DC power for railway electrification. Series-wound DC motors pull like a mountain goat, and locomotives are big enough to solve the handling issues.
Suppose the railroads electrified very, very early, so the very first electricity in any town showed up in the 1880's as the railroad's trolley wire. All the depots and freight houses would be electrified first, followed very quickly by the rich people. Since 3000 volts DC is an awkward voltage to use for residential lighting, the railroads would provide M-G sets to knock it down to 100/200 split, 100 for light bulbs, 200 for motor loads. (Later bumped to 105 and 110V to increase system capacity).
This would spread like wildfire and the whole country would soon be electrified. 110 volts would be a household word. (Even though later they bumped to 115 and 120).
Local/regional generation makes sense
Before electricity, every town with a river had a mill pond. Those mill pond operators decide to install generators and backfeed the system, since it's much, much easier to synchronize into a DC grid than AC.
And then, Aermotor comes out with an electric generation kit for their windmills. While they only officially support off-grid local use, they intentionally design it so it's trivial to make it generate into the grid. Sales explode. The year is barely 1900 and home generation is already a thing.