I'm younger than emojis themselves, to be perfectly honest, but I hardly think that an (incorrect) ad hominem makes my point any less valid.

Emojis have no relevance to how technical someone is

Exactly, they have appeal to people independent of technical skill; hence my hypothesis that they make sure to emphasize the things that are more likely to resonate with larger groups of people (like emoji) rather than things like Project Treble or a "native C/C++ API for high-performance audio", even if the former really have little to due with the OS itself.

If we're going down that route, it's also worth noting that "old people" such as GP referred to also can like emoji; my parents and grandparents enjoy using emoji.

GP's point wasn't that emojis shouldn't be updated, but that it shouldn't require MAJOR/BREAKING VERSION updates (kernel, libraries, the works) to simply update a sprite font.

Who is saying it does? They are just releasing them at the same time.

I don't think they're retroactively releasing them for versions of Android prior to Oreo, though, are they?