I think I understand why. Mathematical logic research has largely become focused on problems that, while important, seem very arcane from an outsiders perspective (even by the standards of other fields of math). The fundamental results of classical recursion/computability theory can be developed and presented with a fairly small amount of logic (see something like Cutland or Cooper). I'm not really super informed on the current state of the field though, so I may be misjudging the situation.