So let's suppose they find this throw-away bat phone. It's been buried. It's been out in the weather all this time. Dirt could seep in if the case wasn't totally sealed--then again, cell phones, at least the regular kind, can be opened to insert/change SIMS card. And then there's the openings for connections.
If they're just the average bat phones that are cheap, cheap, cheap, they're not going to have structural integrity to stand up to the weather, especially damp and rain. And who knows if their SIMS cards are actually anything but cheap, not-intended-to-last-long things? There *are* differences in materials used in making computer chips, SIMS cards, and also differences in how they're made (how skilled is the labor, how clean is the factory, etc.) and that would affect the overall durability.
If they're a cheaply-made device from overseas sweat shops, chances are that the components are cheap and shoddy, and that manufacturing environments aren't exactly clean room.
LE is well beyond grasping at straws, IMHO. They're praying for a set of twigs that will somehow arrange themselves to spell out the name of the perp and they're sure it starts with T. (sarcasm intended) From the get-go, their investigation has been focused on finding ways to prove that TH did something to Kyron vs. finding out what happened to Kyron in terms of multiple possibilities. JMO, of course.
As for Bruce McCain, shrug. He's working hard for his 15 minutes of fame and further chances to wind up on Nancy Grace or other shows. Might as well bring in any other ex-cop to speculate. He has no inside knowledge or connections, IMHO.
I was so afraid that they would find a body yesterday; that thought made me so sad. But turns out they haven't so far. And if they're putting everyone, especially the searchers, through this for one throw-away cell phone--they'll look really really dumb.