Yes, pedantic. Wine existed before Proton, and Valve made it more suitable for use in its own ecosystem with funding and developer time, but also still open and usable for the community writ large.

They've also been funding FEX since it's inception, and likewise commiting development resources for the same purpose, to further their product reach on a wider array of devices.

They aren't simply gobbling up these fledgling FOSS projects for use in their products as you seem to suggest, they've had a long term plan to make milestones and goals that have gotten them to where they are now. That's the point.

They aren't gatekeeping anything. They simply have the resources to give these projects they are interested in a boost.