Wanted: Easy Promotion Strategy? Just Say It and Do It.
You take no risk, you get no return.
The questionable method solves the problem; the "safe" method leaves you with no solution at all.
The essence of managing self-expectations is indeed sunk cost.
Because expectation management, at its core, simply asks: what's in it for them if they listen, and what are they losing if they don't? Whether you're managing others or managing yourself, it all comes down to this. And if you want to manage others' expectations, you must first manage your own.
Only when you truly take that step—when you throw your knees onto the field and let capital see the wolf-like ruthlessness and resolve deep in your pupils—will you get funding and see entrenched interests make way. Otherwise, you'll just be picked on as a pushover, squeezed until you're dead. Because you haven't changed their decision model. You haven't changed their expectations.