It’s interesting that you mention Garmin - they’re a good example of pivoting from your original market (standalone gps units for cars) once you see a nimble competitor eating away at it (gps-enabled smartphones). Garmin would be dead if they had held fast on the standalone GPS market.

I'm not sure you are fully aware of the markets that Garmin is in. When it comes to marine, aviation and offroad, you simply cannot run a gps app on a phone. E.g.

https://www.garmin.com/en-US/c/aviation/general/