Larry...
My best guess (and mind you this is just me spitballing - I don't know) tells me that at most the last device or two offered on a carrier might get upgraded to Windows 10 Mobile.
This is the way carriers think. They want you to buy a new device. They know you want a major OS upgrade and they hold it hostage for just that reason.
In terms of Vzw that would be the 735 or the Lancet...