Arch Linux drops Python 2

Which standard is this that says that python should not point to python3? PEP 394 as you mentioned clearly allows for the Arch behaviour. Please tell me which PEP contradicts this. From a quick search of PEP titles I cannot find any PEP that overrides PEP 394. "rfc2119" that you quote is just the definition of "MUST NOT", so not relevant. Frankly, unless you can back up that statement I call BS.

And those scripts that expect python to be python2 would be broken anyway on a system without python2, so there is functionally no difference (it is not like any of the scripts are going to actually work but do the wrong thing, they are going to fail outright, or just happen to work, unless explicitly written to create different behaviour).

Oh and I haven't seen a python2 script in years now, so I doubt that much of that "enormous corpus" is still actively used by typical end users. Sure there will be some old server or industrial control machine running some old CentOS version that is no longer supported with python2 scripts. But they are most probably not running Arch anyway.