> threading is also disabled or behind HTTP response headers post-Spectre
It seems like you've written a long-winded complaint that you have to add a http header (like this[0]) to your server's response? Though it's true that the Spectre stuff broke everything for a little while there (and there are still ergonomics-related teething problems with headers that are being worked on).
> Games need UDP style non-guaranteed networking, but we only get this as a tiny part of WebRTC (DataChannels).
WebRTC DataChannels work fine though? Does it matter that it's a small part of the whole WebRTC spec or that server-client use is a bit of a hack? Either way, WebTransport hits origin trial in Chrome in about a week, and it's specifically designed for UDP-like client-server communication, so the WebRTC approach can be swapped out once that is stable.