Google bought widevine last year. Now you can use it on raspberry pi, and other devices. So while true, your statement actually is an example of google making the infrastructure more available under the google umbrella.

Google didn't invent that particular DRM, but now that it's widespread, they have bought it outright.

I don't know if their purchase included the rights to open source it in the near future, but it wouldn't surprise me.

However, Amazon Prime Video, BBC, Hulu, Netflix, Spotify and Disney+ all use widevine, so I imagine there are more companies at play in this scenario than just google.