I don't work in the industry, but as an outsider your question seems to answer itself. I would wager that Unity wants to take the step from the hobbyist space to the professional space — because surely that's where the bigger sums are made. Even if they're not there right now, consistently putting out content that indicates that you're working on it is a great way to captivate your audience over time and shift the perception of what your brand is about. In the startup space, this would be similar to building in the open — it helps you signal your brand, build a reputation and, hopefully, build a customer base that matches your sell.