>>19
vi is standardized in the IEEE standard 1003.2.

>>21
Emacs isn't installed by default for the simple reason that it's HUGE (and not because it sucks)

>>22
As for vi, it won't be removed (at least from BSD) because:
- It is small
- It is easy to use
- It's been there for 25 years.
- A lot of people still use it (even if not for everything).