Since the Steam Deck solidified handheld gaming PCs as a category, alternatives from Ayaneo, ROG, PowKiddy, and Lenovo have flooded the space with a raft of options. Competition and device choice has become oversaturation.
There are SteamOS-like alternatives for other handhelds though, like ChimeraOS and Bazzite, and in many ways they even work better (due to faster updates, more software/frontend options etc).