Just two thoughts...
Six months seems like a very time... just on the face of it... and therefore I feel for anyone who would have to suffer such a fate. But... admittedly... I don't know how many projects are typically completed in six months. I'm going to guess, depending on on the project, between two and three? Why aren't people sidelined by X number of projects, rather than a time period.
Everyone needs a free pass now and then. So, going forward everyone gets one ... only if... the project is no more than X number of days late.
Okay, three thoughts...
If it's well established what works... eg: time frames and modes of shipping... then it's not "unfair" to set expectations. Now, if it's discovered that what worked before no longer does... then new parameters must be set... and in turn... new accountability standards reestablished. <~ maybe it's time for that?