> Let everyone else use TAI, and in a few millennia when high noon isn't noon anymore, we'll worry about it then. Or when we exist as a society on the moon and

> Let everyone else use TAI, and in a few millennia when high noon isn't noon anymore, we'll worry about it then. Or when we exist as a society on the moon and Mars and in the asteroid belt - and the relevance of the rotational angle of earth will be no more interesting to almost everybody the same way local time in Greenwich UK doesn't matter to 23/24ths of the planet. (Hopefully that's well before the "few millennia" it'll take for TAI to be radically different to what we use UTC for these days, and "soon enough" that it's worth taking into account already.)