According to an interview between Valve coder Pierre-Lou Griffais and CNBC, Valve hasn't looking to update the current Steam Deck technology for a few years now. Griffais stated in the interview that:
"We think that it's a pretty sweet spot in terms of being able to play all the experiences from this new generation and so far, the new releases are coming out with great experiences on Steam Deck. Obviously, we're working with developers on future releases and we're monitoring the feedback there but so far, I think it has been pretty good on the horsepower front."
The Steam Deck was first released in February of 2022 and has seen consistently good sales since then. Games are constantly being modified, changed, and optimized to run on the handheld so that you can play your entire Steam library from the comfort of your bed, or while traveling.
A significant increase in Steam Deck power probably won't come for a few years, likely in line with a next-generation cycle, and even then Valve may still support the original Steam Deck for years to come, especially considering how many people have adopted one of the devices. With games such as Baldur's Gate 3 already extremely playable on the device, and even more coming down the line, it'll be interesting to see how big this handheld gets.