'You would think so but a dedicated gps unit tends'
Conversely you will also find that many dedicated GPS units have a finite access to data for accuracy etc
However, last I knew, the iPhone samples every 3 seconds.
But that must be the exception, being a premium metal device, designed primarily for looks and even operating in a very different way to smartphones in general. I even imagine it is quite fussy on positioning too, like a dedicated unit.
One thing for certain, competition means smartphones(more so the functionally inclined ones) and dedicated units will benefit from newer better chipsets.