I think I didn't so much learn new things so much as I got an applied perspective on things that I had already learned. It's one thing to read about value added in a textbook, it's another thing to actually experience it in person buying reagents and selling potions in WoW. You can read about the benefit of fuel transferring lifting stages (aka "asparagus staging") in an article it's another thing to reach that design in KSP, and understand why SpaceX tried to do it.
Especially for more abstract topics like, why does a market work better at discovering information than central command-and-control?
A game can't help but have some mechanisms. The mechanisms don't necessarily reflect reality, but they have to bear more weight of themselves than eg just a story does.
Game design shows at least some unintended consequences.
Especially the more simulation type games like Sim City where the game world ticks along without your input, as compared to more heavily scripted player focused games like an FPS.
You're making the massive assumption that someone plays a game with the goal of learning something. Learning is something that happens subconsciously during game play and that's why games are so effective. I played KSP for a few months but I would never go out of my way to learn orbital mechanics or rocket design on my own. If you told me I need a 4-5 year degree then I wouldn't even start.
Heck, I wouldn't even start with a short technical book because I have no reason to read one. In KSP you are put into an environment where your learned knowledge is actively useful in completing game objectives. The reality is that people would just skip learning entirely.
I also take issue with the idea of hyper optimizing learning as a beginner. Most people don't know what the most effective method of learning is for a given topic is precisely because they are beginners. Even if someone wants to actively study a topic it can take quite a while to get into the mindset and find the necessary resources. You know what? Finding a good game is hard but finding a good book can be even harder! Usually the fastest way to find good books is to just read a lot of books and eventually you just happen to read a good one. Learning the same thing that the game taught you through books probably takes more time than you think simply because the book would have to be equivalent to the game.
The takeaway should be that playing a game and active studying are so far apart they might as well not even belong in the same comment.
