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.
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. 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
I use FontForge because I'm a pleb hobbyist without a Mac, but it's like comparing yachts and life rafts.