A Quick Neuro-Linguistic Observation

The linguistic distinction between non-sex based gender systems or more than three genders for male, female and neuter (a common feature, for example, of Niger-Congo languages, Papuan languages, and Australian Aboriginal languages), and noun cases that are not called genders which are present in many other languages (which are numerous, for example in Caucasian and Dravidian languages), is a distinction without a difference in my opinion, that obscures possible relationships between languages based merely on regional and sub-disciplinary conventions about how grammatical features are named.

It is also notable that both these non-sex based gender systems and these noun case systems tend to correspond to taxonomies of nouns that neuroscientists have found of distinct modules of kinds of nouns in the human brain.  Thus, while these seem like arbitrary categories, these categories may be to a significant extent hardwired into our brains, which suggests that these categories were likely also part of many Upper Paleolithic human languages that were never attested.

The fact that these language features are most common in some of the language families derive from language families that have probably existed with very deep time depths also supports this hypothesis.