The main reason is that no research in static typing have found how to type the function self() in an actor model yet. There are some typed language on the BEA

The main reason is that no research in static typing have found how to type the function self() in an actor model yet. There are some typed language on the BEAM but far from being reliable on prod. Quite simply, noone knows how to efficiently type the actor model on the BEAM yet. It is that simple