I'm having a hard time finding people writing about this, because so many people write about shells from a more recent perspective. According to this, tcsh introduced completion in 1983.
I also found in the bash changelog from 1996 there are fixes to crashing bugs in file name completion.
However, I stand by what I said. It was common for people not to know about filename completion. It was common to ship without it by default. Most clued in people installed bash on those systems. But not everybody.
https://developer.ibm.com/tutorials/l-linux-shells/
Early on it used esc instead of tab.
I also found in the bash changelog from 1996 there are fixes to crashing bugs in file name completion.
However, I stand by what I said. It was common for people not to know about filename completion. It was common to ship without it by default. Most clued in people installed bash on those systems. But not everybody.