PRISM was "unlikely to happen" too. The ability to conduct surveillance through consumer devices, however, is something that already exists (cell phones [1]). Given that the NSA record private phone conversations en masse, as well as many other types of data, why would you assume it "silly fearmongering" to suggest that they'll continue to develop and improve their system's capabilities?
I'm using your words, it's not a matter of "likeliness", it's simply a thing of which we have zero evidence or indication that it is going to occur.
So yes, I do think it is "silly fearmongering" to suggest that they'll continue to develop and improve their system's capabilities in the specific way you're suggesting.
>I do think it is "silly fearmongering" to suggest that they'll continue to develop and improve their system's capabilities in the specific way you're suggesting.
Why would they not exploit a capability that they have indicated interest in exploiting given that they've already crossed the line into illegally collecting as much private information as they can?
They sold the AT&T facilitated phone tapping as something they would do selectively, with FISA warrants. It turns out they were conducting mass collection of conversations and conversation-related data without warrants. Why would they show restraint with the ability to listen through consumer devices? Talking about scenarios that are likely to happen isn't "fearmongering" it's rational vigilance given where we're at.
How is it not technically possible to collect information from consumer devices that are connected to the Internet and where the vendors cooperate to provide backdoors (as they do with cell phones)? As for politically feasible, it isn't politically feasible for them to collect everyone's communication via PRISM, yet they are doing it.
Preventing government abuses means paying attention to not just what they've already proven to have done, but also attempting to discourage them from taking likely next steps.
[1] http://news.cnet.com/2100-1029-6140191.html