That's generally one of my bigger philosophical issues with 5E (and D&D more generally). I like games with broad classes where the flavor is assumed to be put in by the player. I like games with specific classes, where the classes map strongly onto in-game lore. I get annoyed when the game tries to split the difference, like D&D does when you contrast something like paladin with fighter.
That's true, but I think that's a feature, or a bug (?), that's always been with D&D to a greater or lesser extent because of the very nature of how it originated.
The original two classes (Fighting Man, Magic User) covered the entire spectrum of two archetypes.
Then, they added a third, gish, class that also happened to be weirdly lore-heavy for bizarrely specific reasons (the Cleric as a Van Helsing type).
Once you have those three (basically FIGHT, SPELL, and GISH) everything that came after it became more lore-heavy, with the possible (possible!) exception of the Thief.
Halflings, Elves, and Dwarves were Tolkien.
Rangers were Strider. Paladins were Three Hearts. Assassins, Bards, Illusionists- all weirdly specific "subclasses." The Druid was a very specific conception of Sustare's idea of proto-Romano-Celtic ideas that were around in the 70s. And the Monk was straight-up Remo Williams.
Since then, you have the same issue. You have to include the lore-light core classes (such as Fighter, Wizard) and if you want some continuity, you also have to make a place for the other classes that mostly exist because of some tie-in to traditional lore.
IMO, etc.