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 was looking at some old pictures of my family and some of them had dates like 921 for 1921 in them. I used to abbreviate 88 for 1988, but I’ve never seen people using 3 digits like that.