A former Tech leader where I work used to say "Never say you can't do something. Just provide options, cost and consequences. The business/management/client will make the decision for you."
This is super important. Having someone come to the conclusion you care to on their own will solidify it in their own heads as their idea, making it an obvious choice. I’ve even gone so far as to argue against it with a few surface arguments, to cement it in their minds.
Is that manipulative? Sometimes. But if it’s for the benefit of the team, you do what has to be done.
I imagine this leading to situations where you say things like, “pursuing option X would require a research project of indeterminate cost and time, likely longer than 7 years for a 10-person team”
One place where this can fall down is when the cost is along the lines of "if we do X then we're closing down the option of doing Y" later.
Unless the business/management/client is better than average, there's a large risk that they'll say "fine, whatever, we want X", then a year later ask for Y and be unhappy that it's impossible or very expensive.
"A cynic knows the price of everything and the value of nothing."
Marketing / sales / bd / etc do not understand most of the variables engineering is working theough. They can be big: impacting price to build/extend and when it starts being a profit center! The tricky bit is those depts also have their own tracked variables that need to be rolled into the decision. Non-engineering variables can also be critical: E.g., going to market before others, hitting some top account or partner, growing revenue by x% compounding now and using that to pay for tech debt, or even learning the workaround isn't worth improving from the customer's/market's perspective.
The humbling thing is no one has all the info, from engineering and product to sales and marketing to the execs. That is where your job comes in. So communicating opportunities at the level of time/cost/growth within engineering's field of view, and making this a non-unilateral discussion. (And if you are good, invisibly sneaking in color around all your other operational glue: who is doing well, what new ideas came in, etc.)
Is that manipulative? Sometimes. But if it’s for the benefit of the team, you do what has to be done.