I'm often reminded when I rewatch TV shows like this from the beginning of what stardestroyer.net calls "Brain Bugs" -- which in their case was refered to as a tendency to as time goes on in Sci Fi focus on one or two specific traits of an alien society as a lazy shorthand for depicting them, as opposed to expanding them with a richness. So, the Ferengi over time became all about money and greed, ignoring that on TNG they had an established military, weapons, and other things that later Trek ignored to the expense of effectively making them a one-note cartoon society. Likewise, Klingons all wearing body armour (even civilians) and being drunkards who fight and are obsessed with honor. Early Klingons, even the TOS movie Klingons, had more strings to their bow. Your betazoid example is another great one. Early TNG gives us some intriguing ideas about how different their culture is, but over time they *just* became about their empathic ability and that's it.
It's a general phenomenon, tends to happen to a lot of characters (or in this case, races), over time, I think.
https://tvtropes.org/pmwiki/pmwiki.php/Main/Flanderization