That's pretty shaky ground too, even if you can overlook the foundation being closed source, Valve aren't really known for supporting their engines very well beyond their own internal needs. They're not trying to be Epic or Unity.
The most obvious aspect to that is that Source 2 doesn't support consoles. Valve don't need it, so they didn't implement it.
> Valve aren't really known for supporting their engines very well beyond their own internal needs
They don't need to. S&box uses a fork of Source 2 that is maintained by Facepunch, with Valve's upstream changes merged in as needed.
Dude. People are playing and making Gmod and HL2 mods and maps to this day. How many 20+yo game engines can say the same?
> Valve aren't really known for supporting their engines very well beyond their own internal needs.
Valve has a long history of supporting the modding community and outside users of Source, not sure where you're getting your information from but I don't think they've worked with the Source engine before. One of the biggest and most popular mods of all time was built on Source, and took the world by storm, with pretty big support by Valve through the years as well. Eventually they even bought the whole IP.