That's not my experience. Granted, I've only relatively recently reached staff level, but I've been working with other staff engineers (and higher) for a rather

That's not my experience. Granted, I've only relatively recently reached staff level, but I've been working with other staff engineers (and higher) for a rather long time, including through some re-structuring. Their role seems to have stayed similar, and they still "architect". But more generally, I think what you describe can always happen, whether you have the "staff" label attached or not. Especially when you get a new manager or management chain, they can always have a different idea of what you should be doing. If anything, I feel that as a staff level engineer I'd have more pull in resisting those changes (if unwanted) than otherwise.