Asm.js was never needed as a legacy mechanism, as it was just a compilation target for native code. There was nothing that it needed to remain backwards compatible with, all asm.js code was new code.
Asm.js was never needed as a legacy mechanism, as it was just a compilation target for native code. There was nothing that it needed to remain backwards compatible with, all asm.js code was new code.
OTOH asm.js can be retired now thanks to being backwards compatible with plain JS.
It allowed it to be an experiment that could have been quickly rolled out without a risk of forever lingering as a back-compat requirement for browsers.