What are they gonna do, add proprietary extensions? Nobody will support those. It’s open, and it only works by being open. It’s actually in Google’s interests for it to be open, widespread, and an effective format because it saves them bandwidth and improves UX on their actual proprietary stuff like YouTube.
Then projects would just not update to the new standard, pretty easy solution. Is webp even changing anymore?
And how would Google start collecting license fees? They already give away this IP, so they can’t just undo that.