Indeed, it seems that the whole game was built backwards, if that was supposed to be the goal.
The two rock-bottom simple combat options, Berserker Barbarian and Champion Fighter, are....poor, shall we say. The former pays dearly to use its fundamental feature and doesn't really get anything to compensate for that. The latter critically (heh) depends on getting lots and lots of combat rounds per day--as in, as close to the maximum stated amount as possible--which doesn't happen in real life.
Meanwhile, all other non-spellcasting classes are relatively complex in combat, while having literally almost nothing whatsoever to do out of combat other than "petition the DM and pray for a favorable ruling" and "check equipment list." So if you don't want to be a spellcaster, you choices are "something that doesn't keep up in combat and has no options out of combat" or "something that's finicky in combat and has no options out of combat."
Alternatively, you can be a spellcaster! ...where there's literally only one option that is somewhat low-complexity while in an actual combat (Warlock). Everything else rides pretty high on the combat complexity scale, other than maybe Paladin. Now, these options can totally do all sorts of stuff in the world outside of combat, in fact they're practically overloaded with tools for addressing that stuff if it catches their fancy.
So...you can be a spellcaster and be somewhere between slightly and severely complicated in combat, and actually feature-rich and complex outside of combat...or you can be a non-spellcaster and be somewhere between dirt-simple and low-performance or moderately effective but moderately complex in combat, and almost totally feature-deficient outside of combat unless you use spells (looking at you, Totem Barbarian and Eldritch Knight.)
It's like they heard the lesson, and articulated it, and then chucked it out the window and did what they wanted to do anyway.
(And, because the odds are literally 100% that someone will say something about this: Skills don't count. Everyone gets skills. That's not a feature provided by the Fighter class. It just straight-up isn't, and I guarantee you won't convince me otherwise. Way too many people have tried, none have succeeded.)