I'm going to address a few points in your question individually:
Certainly licensing is part of Open Source, but it's frankly a small part, and in addition few attorneys post on this site so answers about license details are of questionable value.
Licensing may be a small part, but it's also the trickiest part that I believe brings in a higher number of questions. These questions aren't poor or incorrect by virtue of their topic, and answers to them don't need to be supported by legal qualification. What matters most are answers that are argued and supported, ideally by respectable and authoritative third-party sources. Content policies on Stack Exchange also protect any misinterpretation or other issues with respect to the content that users produce.
A significant portion of our site is based on licensing, with striking parallels between here and Cooking SE. Early stages of beta bring forward numerous artificial questions, and those questions then set precedent and tone for future site development. Questions of management and interaction are organic and when artificial, can be very broad. So it's understandable that licensing became a big deal.
Another issue is that Stack Overflow is a network of technology sites. We have sites for coding, practices, frameworks, cryptocurrencies and so on. People may ask elsewhere. Heck, Stack Overflow still gets tons of questions on the open source tag.
That said, I strongly believe in the need to diversify. However, I don't want to sacrifice question quality for this. Question lotteries and topic contests are successful (especially on Code Golf), and while it might work here, I don't see it. Perhaps we should change areas of the tour page to explicitly include questions of management, interaction, and platform (e.g. Github) usage? I don't know. I am open to any other ideas that pop up - and if you think of any, do post on meta. If we [the mods] believe it warrants lots of discussion and visibility, we'll slap a featured tag on it as well.