Hello Stellaris Community! We’ve seen a number of your reports regarding the pop growth mechanics included in the 3.0 Update. We’ve been reviewing this feedback, and including it in our post-launch support for 3.0. Either this week, or early...
forum.paradoxplaza.com
As I said, they already do it. And, really, truly, it's an incredibly common and simple thing within the industry. They already have the build they're working on, because that's how software development works. Opening that build (or often one build behind the current dev build so they can be responsive to feedback) to public comment is truly not a major commitment of resources. You appear to be approaching this from a... highly formalized and structured concept of a "beta test," I suppose, and that's not at all universally applicable. There is no "find the correct users for testing" step in an open opt-in beta, for example.
Regarding GitHub, I brought it up as an example of how forked and branched software development works on a scalable level - those ideas are not unique to GitHub. Rather, GitHub is structured that way
because that's usually how software development works. They made it with software developers in mind. The structure of GitHub is responsive, not prescriptive.