Then End Of Garmin And Tomtom Units?

[Oddvar]

Phones these days are capable of running all maps that GPS units can do. A bit awkward to zoom and operate while riding has been a problem so far.
Below is a concept from Thork Racing. Expensive, but other suppliers will follow and prices will drop.
Any old phone can be used for navigation. Thork racing have developed a handlebar controller for Android and selling it expensive.
Check the web page for video and more info: CARPE CI Controller - Thork Racing
I just got a new Garmin Montana which I think will be my last GPS unit.

 

[canthai]

My Zumo refuses to die. but when it does I doubt I will replace it.
As you said GMaps can do everything it can

 

[Oddvar]

I played a bit with the Drive Mode Dashboard 2 app and one feature stands out. The UI !.
Operating a phone on a handlebar mount while riding is tricky at best.
The UI (User Interface) override the Android UI. So if anything pops up on your screen, phone call, message or so the UI will take you back to whatever map you were using. Worst case you have to swipe to left.
The benefit of using an old phone without a sim card is no interruption while riding.
(Use wifi when updating etc.)

The main screen with Odometer.

The app screen. Easy to add your favourite maps.
Maps needs to be installed on your phone prior to inserting them on the app screen.

A paid log book for those who like to keep track of their rides. I guess there is a share button in there too.
Download the free version and check it out.
A bit of advice: You will need to shut it completely down when done, otherwise the UI will be active. I have used an old phone to test it. Will never put my "main" phone on a handlebar mount.
Easy fix, restart the phone when done.