These are all things people said about BlackBerry and you do have a point for now, which is why I said "yet".
I have and use the Garmin tech, it is more feature/function and is more suitable for rugged environments and use. But relying on those (relatively niche, and I live deep in the mountains, in a very remote area, hunt, fish, run, climb, back country ski, etc at least 75% of the year and 5min from my house in any direction there is no cell service for an hour, so I am most certainly a "niche" user and I still see the writing on the wall).
I'm not talking this year or next, but those who think Garmin is going to retain a hold on the market on some rounding-error of an application or niche are ignoring the economics and history of the reality here.
In a few years, an iPhone or Apple Watch in an Otterbox-like ruggedized casing will make all that such a small niche that Garmin won't be able to sustain a viable presence in the market.