Most contractors scroll past sources sought notices. They look like noise. No money attached, no contract to win, no clear next step. So the notice gets skipped, and a month later a solicitation drops for that same requirement and the contractor wonders why it's structured the way it is.
Here's the part nobody tells you: the way that solicitation got structured was decided partly by who responded to the sources sought, and what they said. If you weren't in that conversation, somebody else was.