This doesn't seem like a mistake other than how it is the obvious lead to the scope creep, maintenance creep pipeline. Python having an highly capable standard lib is exactly why some people love it, specially "10 years ago" when it was very slow to rev up your machines that need to be very much isolated from other machines, and you just had to have a bright enough person on systems making sure everything was included from the get go. Python saved the ass of more than 0 people reading this discussion right now on that merit alone.

I think there's a simple solution to all this. Libraries targeting third party protocols get an expiration date and have to forcefully be replaced by name after a given number of versions. Even if they keep the same underlying code, still change the name to force developers to look up its usage and legacy. How many versions? However many equates to the threshold you use to call most systems "legacy". I don't mind some job security and some timebomb punishment aimed at dinosaurs. I have bigger and more consistent issues with that than with weter or not C++ let's me crack a .rar without extra libs.