I wouldn’t say that people who like 5e simply don’t know any better. One of the faults of the idea of “good” design (in any field) is that it takes particular solutions to be universal. What to one person might be tight, complex, player-facing game design might be overly elaborate or get in the way of another persons playstyle.
In other words, some players might love their Dragonborn hexblade sordinlock but want moar customization through feats and other players (I’ve seen plenty of them) are good with “elf with bow” as their entire character concept for an entire campaign