Haven't you heard? Valve never releases a third version of anything.
>Furthermore Source 1 didn't really get outdated as such, it got iterated on numerous times before introducing Source 2, which I assume will not be "completed" until Source 3 gets named the next version.
The main outdated thing about Source 1 is the authoring tools, which haven't changed much since Half Life 1 was released. Source 2 is supposed to fix that.
Source does rely on several other technologies (i.e. Miles, Blink, Havok) that you must license from their respective license holders, however Source is free to use if you're distributing on Steam and you only need to license the Source Engine for distribution off Steam or if you choose to distribute the SDK's tools with your game.
So with that in mind, I doubt the rely much on licensing fees as a source of revenue.
Do you have source for this?
https://www.reddit.com/r/The_Gaben/comments/5olhj4/hi_im_gab...
Although this is from the Chinese press conference, and Valve hasn't confirmed it officially, it's at least credible.
Source 2 was patched into Dota 2 years ago, and being patched into CS:GO this year.
Furthermore Source 1 didn't really get outdated as such, it got iterated on numerous times before introducing Source 2, which I assume will not be "completed" until Source 3 gets named the next version.