[mixmastamyk]

This is the common rebuttal, but rarely mentions alternatives to timezones.

One might be a clock face with local solar time as light/dark patches portraying the "movement" of the sun. Perhaps digital UTC in the center. A button to switch cities, etc.

I've seen a few implementations of this with LCD clock faces. They don't typically show UTC as well, but could. Once implemened getting everyone to use it would be the hard part.