Funny, the article doesn't mention failing power systems, load capacity limits, or allowing frequency excursions (term of art in the power industry) saving power or making it go farther. I think you read far too much into it.

Phase angle/frequency correction is an ongoing, quite time consuming and expensive, housekeeping duty with any power system. Failure to keep the frequency within the previously tight standards saves the cost of constant adjustment but it doesn't make the existing power go any farther.

The down side is that cheap and non-critical devices are the only ones which use the line-power frequency for timing. All the critical systems have timing devices independent of the line power. Typically a quartz crystal. Fact being that their example, a coffeemaker, and cheap clock radios, are pretty much the only pieces of equipment which immediately come to mind as being line frequency based.

In the industrial sector motor RPM is dependent on line frequency but the industrial sector has a lot of experience in handling this. Critical systems, and a whole lot of systems which aren't critical, have shifted to steppers and VFDs in the last twenty years simply because they offer finer process and power control, and higher efficiencies. Every year more motors are shifted from 'dumb', line frequency limited, to variable frequency.