I'm not exactly sure what kind of discussion you want to start here. Can you be a bit more explicit?
I haven't look at many text-based tutorials, but I assume they more often end up being better than video tutorials, because they can be updated and because one has to write down and think about the what has been written, they tend to contain less random babbling, which in video tutorials can lead to people talking about topics they actually have no idea.
The state manager from the City Building tutorial would be a good enough implementation, if he used smart pointers. The use of manual memory management makes it "unsafe" in a few places.
I don't agree with some of the coding conventions (this->, one-line if-statements, etc.) he's using, but then again, that's a personal preference.
To be fair though, the focus of the series is on the city building and not on how to create a generic state manager.