This tells me you are either an executive who has forgotten how much work it takes to convince you and your peers that a solution actually works or you are an employee who has not had the experience needed to report up to an executive.

Executives who typically want “conclusion first” for “time savings” often use up the same amount of time or more “backing through the needed explanation.” Does that mean you shouldn’t aim to be succinct? No. You should have talking points prepared. But OP is mostly on the nose. This sort of demand for conclusion sans explanation only to go back over what you would’ve explained anyways is usually driven by external stress.