Flippant but serious question....musicians, especially guitarists, have long struggled with 60 cycle hum (although most equipment transforms AC to DC).
I know that Germany, for example, uses 50 Hz (this caused problems in the early days of Moog synthesizers that relied on the mains power frequency for timing purposes).
Will abandonment of the 60 Hz standard affect ground loop hum?
No. It may change a few hundredths of a hertz from exactly 60.00 Hz, but it will be the same effect. The ground loops will still be there.
In fact, there may be no difference at all as far as anyone can tell. It looks like what will be abandoned is not 60 Hz power, but the requirement that the average frequency over long periods be held tightly to 60 Hz. In other words, the small fluctuations we now experience around 60 Hz may not be very different under the new system, except that they won't try real hard to "catch up" over a period of days or weeks.
A "why" this is a good idea would be appreciated!