he put out a video every week for like 2 years back when he was active, and there were few other resources back then (on youtube it was basically just pishi, Mo, and that one Charles445 polarity video), so basically everyone who was getting into mapping and looking for help with it in 2016-2018 saw a lot of his stuff
then, because he had a huge catalogue of tutorials and other mapping videos and an entire generation of mappers had "grown up" watching them, people just linked his channel every time they saw a new mapper and he became a bit of a household name
I don't really keep up with the mapping tutorial space anymore, but for what it's worth, I haven't heard of anyone matching him in volume or diversity of topics yet, although I hope we get there some day