Badly designed things get replaced. For example unique_ptr replaced auto_ptr. I'm not sure if the language standard actually supports the term "deprecation" though.
Edit: Also not sure what can possibly be downvoted here.
Edit: Also not sure what can possibly be downvoted here.
Regular expressions in C++ are an example "everybody" advises against using, but it's still there. vector<bool> will stay forever and so on.