Linux hit a marketshare of 2.32% in the May 2024 Steam Hardware Survey which marks the highest ever. The last time it went over 2% was in February 2013, a few months after Valve launched the Linux Steam client, when it hit 2.02%. When accounting for just anglophone users, according to GamingOnLinux, Linux represents a 5.29% share. Factors such as the Steam Deck doing well commercially and the concerns behind Windows 11's Recall feature and telemetry may have contributed to Linux's rise.
Things holding Linux back include anticheat software in multiplayer games, Playstation games that require PSN logins, SteamOS still only available on the Steam Deck, and Nvidia GPUs not playing nice. I personally doubt the first two problems will be solved. Valve works on Valve Time, so who knows when SteamOS will be available on other handheld PCs, let alone, regular PCs. There is promising progress with Nvidia GPUs and Linux with NVK making inroads and explicit sync currently in beta.