C was designed to write Unix, but they didn't overfit it for that very specific case only. So it has seen application elsewhere.
Neither was Rust overfitted to exactly only writing browser engines.
Neither was Rust overfitted to exactly only writing browser engines.
Browsers layout and rendering will have some elements similar to that of a game, but it isn't on the same level. A game can usually assume that it's trusted to run that shader, in a browser that's a vector for attack. Security design will impact game engines and browsers differently.
Granted, people are doing their darnedest to make games in the lowest common denominator technology, i.e. Electron.