Re: Yay landfill!
Absolutely they are used.
My phone has a GPS, and also gets FM traffic updates, so it doesn't require data. It's also 5" in size, and has a couple of features cell phones don't seem to have.
But more importantly, it (a) is sunlight readable, and has a non-reflective screen, something that no phone seems to have. And (b) it works based on pressure points, so it doesn't require skin contact. That may not sound like much, but in a Canadian winter, the ability to use your GPS with your gloves on is a selling point.
And that's just consumer GPS. Things like specialty trucker GPS don't really have cell phone apps that can replace them yet.