Bash has had thousands of programs built on it and just on it, no GUI required. Monad has next to none. Bash has advanced features that allow you to pipe and interact 2 or more command line programs. Windows programs are almost always GUI based which means getting them to interact nicely is near impossible. If Monad was able to control a GUI based program (which I have heard it might be able to do) then it would have to have id tags for all the windows (since you can have say 10 IE windows up at once) and it would be slow and extremely confusing. Also linux has advanced priviledges where you can't open or read a file unless you have the proper priviledges, Windows priviledge system is basically non-existant so Monad will be a huge security risk (google "Windows Vista Monad virus") which is why they took it off Vista to be released later.
these are just a few reasons why Microsoft can't quit from command line and bring it back and hope it will be awesome. Thats my Monad bash
for the day.