Use of SharedArrayBuffer in timing attacks was widely predicted and there were working examples showing how it could be used to extract information from browsers long before vendors enabled it by default. It's hard to have faith that the people who ignored all those risks won't do so again.

It would be an existential crisis for several of the browser vendors if they can't add things like threads with shared memory to javascript/webassembly. The existence of those organisations is based on the idea of the browser being a replacement for native platforms, and if they can't include basic and vital features like threads then they will always be at a huge disadvantage to native platforms.

Do you think Mozilla will admit the entire browser-as-platform project is flawed and disband the organisation? Or will they push ahead with these new features despite the risks?