The over-under — that is, the point where there are equal chances both before and after — on the new conservative majority cohort3 all staying alive is just about eight years. The over-under on the liberal minority cohort all continuing to draw breath is about five years.
Justice Neil Gorsuch, congratulations: As the youngest Supreme Court Justice, you are expected to be with us for the longest. There is about an 11 percent chance that nearly-51-year-old Gorsuch is still alive and kicking in 2060 and a better than 50 percent chance that he gets to 2048. Set the over-under for Ginsburg — the oldest justice, at 85 — at around 2025. Kavanaugh, the 53-year-old would-be court alterer, may or may not make it past 2047, with about equal probability.
Of course, what happens next to the court should the end befall any of these justices depends entirely on timing.