The story gets told the same way every time afterwards: they had spent a decade in the industry, so of course they saw it. It is a satisfying explanation and a poor predictor. Plenty of people spend a decade somewhere and see nothing at all, and some of the sharpest operators we work with arrived from outside the category entirely.
What we look for is narrower and less romantic. Does this person already hold the specific unfair advantage that this specific idea requires? Sometimes that is a decade of pattern recognition. Sometimes it is one relationship that opens a door nobody else can open, or a technical instinct that makes an intractable problem merely difficult.
The second question matters more, and almost nobody asks it out loud: what will this person do in year three, when the interesting part is behind them and the work is hiring, pricing, and saying no? Ideas are easy to love at the beginning. Very few people love them in the middle.
We would rather delay a company by six months to find the right person than start on schedule with someone who was simply available. A good idea with the wrong founder does not fail quickly and cleanly. It fails slowly, and it takes the idea down with it.