Captain Kirk Was a Lousy Tech Manager

OP is right about tech/development managers needing to respect estimates but wrong about Captain Kirk.

Captain Kirk pushed Scotty because Scotty was an extraordinary man capable of doing much more than he admitted, if the matter was urgent. Kirk pushed Scotty when he felt that it mattered to the safety of the crew or to others whom they were protecting. Sense of urgency is important both in getting customers to buy and in helping boost team morale, as long as it is used in moderation.

Few ever doubted Kirk as the leader of the ship, and I think even Scotty was entertained by and admired his tactics and style.