manuals (as opposed to ingame tutorials), like free demos, are one of those things that feel like they don't really have a viable place in larger profit focused corporate video games at this point because they eat directly into your general audience, but also they probably should just make a proper comeback in the hobbyist indie space (provided they're digital manuals of course)
besides the fact that ingame tutorials are kind of an enormous pain in the neck to implement if you didn't build around it from the start, a lot of "wiki games" are literally just games that require a digital manual and outsourced it onto fandom dot com
like when you look up where to find ore in a survival game, that is functionally identical to the game having a mechanic that is not explained outside of a manual, it's just the modern version that requires an internet connection