In pointing to Cassidy and Monty I'm primarily asking why shouldn't Sweeney be held to the same standard? Fair point that Monty's time was shorter and more patchy, but insert Julien then instead. When these long-term and mostly successful coaches stumbled and arguably went past their used by date in Boston, rightly or wrongly Sweeney fired them. I think it only reasonable that the GM himself should expect the same treatment.
On the lack of a Cup we simply see it differently. There is plenty of blame for falling short to go around but I believe Sweeney should bear his share too. No GM can be perfect and all rosters have flaws, but there are certain things, like the beyond-obvious black hole on Krejci's right in 2019 that Sweeney didn't even attempt to fill, that IMO were simply erroneous and inexcusable. In my mind I cannot ignore those, few as they may be perhaps, while also giving credit for a lot that Don has done right over the years.
I respect your position. We are not miles apart. I'm not yet firmly in the 'Don must go' camp. But I'm leaning in that direction, pending how the next 5 months or so play out. The issue that probably stands out most to me is something I said in my previous post - weaknesses tend to compound over time. For example, even allowing for the lack of high picks I think Sweeney is not very good at drafting forwards. Defenders, sure, but not the guys up front. And he has never prioritized sheer goal scoring talent, or perhaps even offensive/playmaking talent more broadly, enough. The longer you leave the same guy in charge, the deeper those issues run and the more damage they can cause, however much he brings on the positive side. Couple that with an offseason where he may well have gotten it very wrong indeed (TBC), and questions on whether it's time to move on inevitably arise.
All we can do for now is wait and see what unfolds from here.