Really? You should look at a few non-d20 systems. Oneshotting someone with a stool is super easy in Fate Core, for example, with the math still being balanced. As for Boromir defeating dozens of orcs...that was possible in 3e and 4e, but with bounded accuracy, even a dozen orcs can be incredibly deadly for a fighter. A high level champion would go out like a chump in such a situation. A high level wizard would cast meteorswarm or forcecage or teleport or...well, you get the point.
Really? Fine, let's look at the math.
Worst Case scenario.
Boromir, Human Fighter-Champion. No Feats. Level 15
Fighting Styles - Great Weapon & Defense
Str 20, Con 20.
Hit Points: 10 + (6*14) + (15*5) = 169 (+ 20 points from 2nd wind)
AC: 19 (Plate + Defense)
Attack: +11 Greatsword 2d6+5 (Crit 18-20) Mean damage vs AC 13 = 12
3 Attacks per round kill 1.5 Orcs
Orcs
HP: 15
AC: 13
Attack +5 for 9 damage (Crit 20) Mean Damage vs AC 19 = 3.45
The orcs need 54 attacks to bring down Boromir. Melee attacks. With their Javelins the number becomes 82.
Mind you, we are allowing the Orcs to deal fractional damage, but not Boromir. We're also ignoring magic items, terrain, tactics and his action surge.
Compared to a generic Guard the Orcs have worse AC, but better hitpoints, attack rolls and damage.
Tell me again how Boromir, or any high level fighter is not worth a dozen lesser men, or Orcs?
And of course if we allow poor Boromir access to the optional feat system he drops an orc with every hit, potentially killing 6 on an action surge. He also drops incoming damage by 3 per hit meaning the Orcs will need 76 attacks to drop Bormir. In melee, where he is killing 2 + a round. At range they are barely touching him. Still haven't given the poor guy a magic item though.
Powerful. The kind of fighter that can, as you say, be worth dozens of lesser men in combat. Two dozen guys with simple weapons could easily overwhelm a fighter. The kind who can chop a warhorse in a single blow. A highlevel fighter does 2d6+5 damage on a hit, averaged at 12. A warhorse has 19 hp. The kind of fighter who can jump off a building without even slowing down. Any fall of 10 feet or greater inflicts damage and knocks you prone. In every single one of your examples, you name something that a wizard can do (fireball, sorching ray, featherfall) but a fighter can't. That's...that's kind of impressive, in a weird way.
The Champion chops a warhorse in half on a crit (which he get on 18-20), or with every blow if we allow feats. Jumping off a 2 story building does 11`damage to our example Boromir, out of his 169 total. It's not even worth wasting a second wind on. This is slowing him down how exactly? The guard who followed him is out and making death saves.
The cinematic Captain America who can take down a science fiction warplane in a single round? Yeah, I wouldn't mind playing any of those guys.
Yes, yes, if you give the fighter magic items, he can almost do things like a wizard. This is silly.
I'm confused, are we accounting for Caps unique artifact level weapon in this discussion? Does the fighter get one too?
This forced analogy that magic is equal to technology is ridiculous. It's an analogy whose premise is challenged immediately, and if all parties can't agree on that, it really doesn't have any weight in an argument.
Well, actually I've brought it up several times and you're the first person to challenge it. Would you can to explain where the analogy breaks down? D&D magic is learnable, transferable, it serves as tools for communicaton, transportation, force multiplication, healing, etc. The only thing it does not do is subject itself to industrialization. (In default D&D, in Eberron it obviously does.) Given that there is no industrial, assembly line style technology of any kind in the pseudo-medieval default technology of most D&D worlds I'm not clear on how the analogy fails. Why is the blacksmith employing technology when he smelts the iron and forges the sword, but not when he inscribes runes into it? Why is a ranger employing technology when he tans a hide, but not when he speaks to an animal?
And to be clear, not all magic is learnable or transferable. A warlock, for example, is granted in his spells and probably doesn't understand them. Except for the Tome pact guy who can inscribe new spells in his book, clearly he has some grasp of it. And the fluff does indicate that not everyone can learn or perform magic, although that obviously doesn't apply to PCs. So what? Not everyone can fly a plane either. Color blindness will limit your ability to be a good electronics technician, but it's still only technology.