Let me introduce you to WordStar 4.0, a popular word processor from the early 80s.
WordStar 4.0
As old as it seems, George R.R. Martin used it to write “A Song of Ice and Fire”.
Why would someone use such an old piece of software to write over 5,000 pages? I love how he puts it:
It does everything I want a word processing program to do and it doesn't do anything else.