Why are the power transmission/distribution systems AC and not DC?
There are several reasons. One: power loss in a wire is I^2 * R. Therefore it is better to transmit power at very high voltage and low current. AC is much more easily boosted to high voltage (no electronics are needed). To boost industrial loads using silicon electronics is not practical.

Another is ease of switching under load. If you turn off a load connected to DC, the arcing at the switch due to wire inductance and load inductance becomes problematic. This forces DC switches to be more robust.

The 60 Hz noise created by transformers is much less than the switching noise that would be created by all the electronics required to buck and boost DC and then convert it to AC at point of load as you propose.