Modules have just reached to the point where the tooling is all ready for people to adopt. Right now we are seeing the early adopters start to use modules. We are still waiting to see what they report. They are certainly a major change to how you program C++ and so adoption is going to be slow - retrofitting something new to an existing project is always hard. I still have some C++98 code that has naked new and delete. I'd love to get rid of it but it would be a long painful process to refactor and it's not worth it when the code has been stable for decades. I'm still hopeful that they're a useful thing for the various benefits they should provide, but only time will tell. People who claim that modules have failed because we haven't seen benefits yet are just ignoring the reality that change is going to be slow by nature.