vim is so ubiquitous that most people don't realise vi is symlinked to vim pretty much across the board
The exception is when you go do some work at server using a commercial unix and that is not how it's set up (in fact they don't even know about vim)
sigh but ok that story is dated and that behavior was already dated at that time
I'm struggling to think of the last time I saw a commercial unix -- we still had solaris on some new machines until about 2006 - the last I remember was the x4500 with ZFS.
Our sun sysadmin contractor (whose full time job it was to look after about 10 solaris machines) was a big fan of ksh at the time.
But some companies are even slower to migrate
Anyway I don't know how the builtin shell was called, maybe simply sh but it was also a big no no for me