This is a false dichotomy. "Timely delivery" is also an essential feature of any product.

Or, as they say, the better is the enemy of the good.

While you're "thinking of how to make the best product that you can possibly make" others can just go ahead and make something. And that something, even if it's not the best product that one could possibly make, at least it would exist, then and there, and so would be million times more useful than any project that's still designed in someone's mind.