Joe is going to be 71 at the start of next season, Sam is going to be 78 at the start of next season. I view it more as two guys, who have done their jobs well for many years, are 70 + now, and it's time to retire. Maybe if they felt next season was a SC season they may have stayed, but since Sam announced he was retiring early this past season, and Joe going out after 19 seasons with Sam, and not having a new partner for maybe one or two years, seems logical. I don't read much more into it than that.
I will say, to me, it sort of goes with the theme of a lot of changes before next season. Drury gets the coach he really wanted in 21 and 23, Mike Sullivan. I also expect big core changing moves this summer. There will be a lot different with the Rangers next season, including in the TV booth with Kenny and Cally or Boyle most likely.
I'm excited for it and am very much looking forward to draft week and July. There should be a whole heck of a lot of Rangers news.