It was, but it was (and still is) a Unix tool.
I believe POSIX still requires that more be provided (even if it's just less secretly).
The original Unix more could only go forwards.
Someone wanted to make something like more that could go both forwards and backwards, so he called it less as a joke (because "less" is a "backwards more").
For the past 40 years, everyone's realized that less is much better than the original more, so nobody uses the original any more.
(MSDOS took the idea of "more" before "less" caught on).
Also, sometimes they have an old version of less. There was a change in the past, I don't know, five or so years that made the "exit if less than one page" flag behave better. I don't remember the specifics but it made using it as a fit pager way better. It used to be that it was difficult to have it act like cat when the output was less than a page. But newer versions support it.