This is not just a reminder to elders, it is a reminder to the men who join the cult. After one year, "What's wrong with you that you are not an MS? Start sucking up better."
It took me more than 2 years to make MS from baptized convert, but only less than 4 more to make elder. I moved to a completely different area after that where they never appointed men elders with as few years as me. I suppose different bodies of elders have different takes on this. They did re-appoint me in the new cong., but I understand it was only from a favorable letter and some prodding by a C.O..
I remember conducting a Book Study and I asked "Who has more than 10 years as a baptized JW?" Even my wife, who was baptized as a teen raised her hand. Every single adult in the room except for me, the only elder and the conductor, raised their hand. I kind of did the "Why aren't you up here conducting?" question to the men. (I was fully dubbed over my head at the time and about 7 years baptized.)