Companies that are leading the market are already profiting from existing science, and new discoveries threaten to disrupt the market—it’s often in their interest to prevent new advances from coming to market even if they’d be the ones selling them. (Say, a cheap vaccine that prevents a disease they sell highly profitable drugs to treat.)

If they make these potentially disruptive advances privately, they can patent them to preemptively keep anyone else from introducing them. But if the advances were made using public funding, they have to make the case that whatever they do with it is in the public interest (which can conflict with their own).

The more important factor isn’t the funding or lack thereof, it’s the ability to control the results.