Has it really been that long? Apparently so. Valve originally announced their rebranding of Steam Play with Proton back on August 21st, 2018. Seems like a good time for a quick reflection being halfway to a decade old now with the tech that gave rise to the Steam Deck.
This always happens. Opensource has no marketing and when something is built on top of it, it never gets credit.
Not that I disagree, but they get the exact amount of credit their licenses require… a small-text listing on a “credits” page buried deep in the system settings.