std promises stability to avoid a python2-3 situation. Which means any mistake we make will be with us for a long time. And we've already accumulated quite a bi

std promises stability to avoid a python2-3 situation. Which means any mistake we make will be with us for a long time. And we've already accumulated quite a bit of those mistakes. So non-trivial additions aren't made lightly. Compare through how many breaking changes even high-quality ecosystems crates have gone through in the last few years.