It’s a mix. Partially a systems problem. We used to have that problem, then we changed the way work is selected. Sales is part of the process, so they’re forced to see all the things we could build and help decide which ones were saying no to. They still promise things occasionally but they hedge a lot more now. And our teams delivery rate has increased dramatically because we’re not getting yanked around all the time.
That's not a problem, in the sense that there was never any possible debate: if I make a promise on your behalf, I am a di*k.