"... In a typical gui file manager that kind of stuff is just not possible. The possibility space for what you can do is limited by the visual abstractions the original designer came up with for file manipulation. With command line tools that space is virtually infinite."

whilst i certainly agree with this, i would speculate that 80-90% of the average user's time is spent carrying out a handful of simple operations that are better catered for by guis. for the other 10-20% we have our virtually infinite space: the shell.