Sure that's how people are forced to use TCP, but for performance reasons that's not how they want to use it.

IMO something like SCTP would have been better. You generally want multiple independent streams (to avoid head of line blocking), message and stream transmission, and optional reliability on a per-stream/message basis.

This sort of thing is very very common in real time games (e.g. enet). Actually enet is built on UDP, but if you compile it to WASM then the Emscripten UDP implementation uses the WebRTC data channel which uses SCTP!