@mistersqlAgree with your insights, but not with conclusions:
A sprint/PI/sth-plan is a PLAN, not a commitment.
If you get fired bc plan is met, that's anti-
#agile, it's 20th century style coerce way of work. No one dares giving objective estimates in that case.
I studied some maths: If you plan realisticly, you'll be below plan in - guess what - 50% of the cases. Compensating with slight security adds and just in case some flexible work times, you'll get +/- 80% reliability. More than fair.