@Logicfest -- Some of that might start to change if smart watches ever catch on. Conceivably, there is an item that won't use much power and can monitor someone full time.
Then again, you've got to believe that the folks at Fitbit will have an app or something that will work with smart watches if those become popular enough. Those Fitbits generate a good amount of revenue and shareholders will want to preserve that somehow.
If cash can't be made through hardware, looking at software is the next logical step.