PEP425 stats the platform tag is what distutils.util.get_platform() (and sysconfig.get_platform()) returns.

By that definition - anything is okay, as long as something is returned.

However, in practice, it is insufficient. Simplest case - there is no indication of the fitness of the running Python. This, by itself, may be a reason that VARs and others have never attempted to develop binary (compatible) eggs or wheels.

Looking further at missed potential - AIX has an algorithm that can be used to permit a forward (binary) compatible ABI for packaging. The current state of packaging for AIX is to create an RPM or INSTALLP formatted package - and install that. Even pure-python modules must be packaged in this way - to satisfy the "binary" dependencies.

For a binary compatible algorithm to be possible changes will be needed in pypa tools. However, rather than "patch" three sets of tools to correct the inadequacy of the current PEP425 tag for AIX I propose to tag AIX as:
AIX-VRTL-YYWW-BT or
AIX.{}{}{:02d}.{}.{}".format(v,r,int(tl),bd,sz)

where v=version, r=release, tl=technology_level, bd=builddate, and sz=fitness (32|64).

Further, rather than place this code "inline" in distutils or sysconfig create a new support module for AIX - similar to the _osx_support module (I.e. _aix_support).