Terrestrial Time is a thing: https://en.wikipedia.org/wiki/Terrestrial_Time https://en.wikipedia.org/wiki/Terrestrial_Time > TT is indirectly the basis of UTC,

Terrestrial Time is a thing: https://en.wikipedia.org/wiki/Terrestrial_Time https://en.wikipedia.org/wiki/Terrestrial_Time > TT is indirectly the basis of UTC, via International Atomic Time (TAI). Nobody is going to bother renaming UTC at this point, misnomer or not. Besides, if they stop adding leap seconds to UTC (as is planned) the whole point of UTC goes away anyways.