It seems like it’d get increasingly impractical as the years go on to hundreds of thousands and millions of years to write them out that way, but then…I guess technically one may already do this with the preceding years, so future’s fair game for it?
I would hope that time and date formats would be redesigned by that point. If we would live to y10k, I’d expect a lot of space colonization. At that point, I’d expect there to be some other point of reference to define timestamps.