Valve has been pretty candid about their plans for the Steam Deck, especially around the device's recent release in Japan, South Korea, Taiwan and Hong Kong. The company even produced a neat little booklet to formally introduce itself in new territories where Valve isn't a (specific kind of) household name, filled with tidbits and goodies about the Deck's development and future.
Well, that trend is set to continue, because in a recent interview with Famitsu Weekly, Valve designer Greg Coomer let slip a bit of the company's thinking when it comes to new Steam Decks. Most surprisingly, he indicated that one possibility for a "next generation" Steam Deck was that it "might even become a streaming machine," presumably taking advantage of the Steam Link technology that Valve has already poured a lot of time into.
It makes sense. During the interview, Coomer identified plenty of parts of the Steam Deck that could be up for revision, but he says that battery life is at the top of Valve's list of things to improve. A Deck that lets some other machine—whether it's your own PC or a Valve server—do the hard work of rendering your game would probably hammer its battery quite a bit less than the version we have today. You'd hope that such a device would also be able to cut down on the stuff it needs stuffed inside it, potentially making it a bit smaller, too.
But if you're as streaming-averse as I am, you shouldn't fear. It's unlikely that a hypothetical future streaming Steam Deck would be your only option. Valve has a tendency to talk about the Steam Deck as a "category" of devices, rather than a single, console-like machine that gets iterated on every few years (though they will be improving the current version too). So while the company might one day put out something with a Steam Deck logo on it that plays games by streaming them, it'll probably be accompanied by all sorts of other peculiar handheld PC gaming boxes, one of which will hopefully meet your needs.