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?
At that point we switch to a Year (three digit) and Millennium (M followed by two digits) system, so the year 10,001 would be noted as 001.M10. After 999 M10 we reach 000.M11, and so on. Most applications would only really need the year number. /s