The web is already a game runtime that works on Linux, macOS, Windows, Android, and iOS with decent graphics. I've ported a couple of games. Here's Quake 3 including multiplayer https://thelongestyard.link/ and Cave Story https://thelongestyard.link/cave-story/. There are full-fledged web-native games too such as https://gooberdash.winterpixel.io/ (2D Fall Guys) and https://krunker.io/ or https://venge.io/ (multiplayer FPS)