We already have that ability, both Unity and Unreal can run in the browser (though it looks like Unreal moved their HTML5 stuff into a public plugin). I think G

We already have that ability, both Unity and Unreal can run in the browser (though it looks like Unreal moved their HTML5 stuff into a public plugin). I think Godot also works if you don't use C# and stick to GDScript, or use Godot 3.x instead of the current 4.x. The problem isn't the tech to run the game, it's the marketplace - how do you actually sell the games without losing the huge customer base that buys through Steam and platform-specific stores? If you're popular enough you probably still get a lot of customers, but I doubt it's anywhere near what Steam does for you. Oh, piracy and anti-cheat are also a problem, because you just can't have a AAA game without Denuvo and Kernel Backdoors anymore (greeting to the Apex Legends players out there!). There are probably still a few issues that would have to be solved on the game engine side, but I'm willing to say that the game engine is not the problem with browser-based games.