I remember renting a student apartment in Boston circa 1955 and finding
out to my horror that the place was still on DC.

I was a "Hi-Fi" buff at the time and couldn't put up without AC to run
all my gear, and I didn't want to try and get by with the vibrator DC to
AC inverters available back then.

So, I moved out the day after I moved in, and the landlord was nice
about it.
My God, what COULD you run off DC back then? Let's see, most vacuum
cleaners had universal motors and would probably run on DC, I guess
smaller TVs and table radios would run on DC, but that might be about
it! OK, toasters and mixmasters would probably work, too. Window fans,
electric clocks, and all sorts of other stuff would not, and some of it
would be pretty catastrophic! As for Hi-Fi gear, you'd be stuck with a
hand-crank Victrola! I guess people were more aware of this stuff back
in '55 than today, but I would suspect a LOT of folks would balk at DC
only even back then. A lot of places had multiple supplies, both DC AND
AC back then, as not all appliances could handle AC, in areas that had a
long Edison history. Then, you just had to be careful what you plugged
into where.

Jon