I think every professional type designer I know uses this software.<p>I have trouble coming up with any other example of total domination of a market segment. Maybe Photoshop in its glory days, or Quark Xpress before that, but even in those cases, there were alternatives in (minor) use.
It’s possible you have a small sample.. I have not noticed “total domination” myself. The type foundries I know and sometimes work with are split. Many use RoboFont. FontLab is less common, but there are some shops that have invested in it deeply enough they’re still using older versions, even. And others develop their own tools, like Fontra, to better address challenges in CJK type design<p>RoboFont is deeply tied to the Type & Media program at KABK in the Hague. And it has a long history, building off what came before - it is both font software and pedagogy. My memory on this isn’t perfect but I believe Glyphs and RoboFont were both proposals around the time the UFO spec was being formalized
Microsoft Excel after 1-2-3 (the previous dominator) and before Google Sheets? Word after WordPerfect (close to dominant) and before Google Docs? PowerPoint before Keynote?
Plenty of alternatives to Glyphs. FontForge and Robofont both come to mind.
Fontographer and later Fontlab were totally dominant, and they still have a huge market share.