It would have worked easier back in older editions were a PC class was only a slight step above an NPC and many NPCs were just low level PCs. A decent Hit die with a basic saving throw in to hit progression and a progression of racial or occupational features would be a great help in a party. B/X race as class was kinda this where every dwarf or halfling you see outside their lands got basic training.I'll argue it never really worked. Really, the only way such a character could work (barring narrative tricks and meta-currency) is a skill-based system and a game where combat isn't a priority.
But in Wizards D&D, every PC class in their core books are equivalent to a doctorate in real life. There's a huge gap to fill.