As an answer to another question I wrote out an analysis that, effectively, Stack Overflow is likely close to the point of saturation. Consider the following:
According to Evans Data Corporation, there were 23 million software developers in 2018, this number is expected to reach 26,4 million by the end of 2019 and 27,7 million by 2023. - DAXX
If the 26.4m estimate is correct then Stack Overflow has roughly 42% of the world's professional software developers with 11m users. To put this in context, Facebook has 2.45 billion active users which is about 32% of the world's population (their target user base). While Stack Overflow says their target user base to be "anyone that writes code" I'm not really convinced that you are going to get most of them as registered users. Case and point, in my professional community I know a number of people who write code and will occasionally look things up on Stack Overflow, but don't see the point in asking questions since the answers are already their, or the active user base is on a listserv.
As a result, it appears that if the company wants to see overall market growth they need to focus less on programming (i.e., Stack Overflow and affiliated network sites) and more focus on building the features and user base to support other sites like Arqade (148k users), Personal Finance & Money (64k users), or Worldbuilding (58k users) to name a few. When you consider how many people play video games, it's shocking that there are only 148k users on the site when a Q&A based video game site seems like a great idea.
As such, how does Stack Overflow plan on increasing traffic and the user base of other Network sites?