There are countless fonts at this point. Free ones and commercial ones. Serif and San-serif and everything in between or beyond.
A vast majority of the questions we get asked on this site is looking for a free alternative to a specific font that has a licensing fee associated with it.
So at this point is the font market so saturated and differences so minute that there is very little value in creating a font? Searching online can find countless resources and new tools for the act of creating a font but very little about why someone would want to.
This question, Why would a designer want to purchase a typeface instead of using free ones?, adequately addresses why someone would want to buy a font.
But it doesn’t address, why would someone create a new font? What is the market value?
I can not answer for everybody; I can just provide an answer as to why I have made my own fonts. For me there are 3 primary reasons:
Because I can. As banal as it sounds I just wanted to make one.
The existing fonts were missing technical capability I needed. Since I was using a quite novel system there were no fonts of the type I needed available. No, I couldn’t use a OTF or even a TTF font as they wouldn’t do what I needed them to do.
Copyright. There just wasn’t a suitably licensed font to use as a basis for the glyphs I wanted to add. So I had to make the entire font from scratch.