That timeline would never happen unless the person is an active duty officer who switches to SELRES. We’re talking about non prior service direct commission officers who dangle their toe in the Navy for long enough to put it on a resume but not long enough to complete their initial PQS training and use the training at least once (low bar for success, I know) by doing a short mob or ADSW. So all their Navy time was spent in training as an oxygen thief, and right around LTJG they’ve already pre-planned to drop to the IRR permanently before the Navy even gets a chance to mob them. (This is not the same as the Navy choosing to kick someone out/ let them walk, such as a flight attrite.)
For a brand new 18X5, they would not hit involuntary 2x FOS separation until year ~11 roughly, and the Navy would have had plenty of chances to mob them over the last 7-8 of those 11 years. I don’t fault those people at all if they never were asked to mob (the Navy had its chance). Keep in mind that new 18X5s aren’t even eligible to mob or take ADSW orders until after 36 mo (or 48 mo).
Even new nurses/doctors who commission at O-3 or O-4 would have ~6 years before they could hit 2x FOS. And, they do mob quite a bit.