There are at least 7 commercial passenger flight suicides in history (plus the four on 9/11, though that's arguably a closed vector now, and some others on non-revenue flights). There are around 100K pilots working today in commercial aviation [not all Part 121 (airline)], so perhaps 500K, and surely less than 700K, total over the course of time. If we posit a successful suicidal action rate of 7 in 700K, that's only "five nines" over the course of their shortened career or 99.999%, but could become seven or even eight nines on a per-flight basis.

I'm 100% with you on the desire to not have ground-link control (and, for me, to keep two crew in Part 121 operations); I just figured I'd estimate the math.