We forget what a profound change the back pass law was and goalkeepers had to make it up as they went along. All the strategies and techniques we now take for granted had not been invented.
I believe that not only goalkeepers had to acquire and develop new skills but also defenders and coaches. We even have league one teams building from the back when before we regarded that as continental football. It was fun in the old days though with hoofing, clogging and some players possessing fairly rudimentary ball skills.