Perhaps it was not directly stated. However, much of the OP is saying it is extremely important. I just looked again.
The OP is not about "DPR is king". (It neither affirms it, nor denies it.) It does take for granted that the main mechanical function of a fighter is to deal damage in combat. I don't think that's hugely controversial as a generalisation (a frequent criticism of 4e, after all, was that it had "fighters" whose main mechanical function was
not to deal damage in combat).
I've sblocked sections of the OP, then comment on them.
[sblock]
In the beginning there is the fighting man, doing 1d8+5 with his sword once per round (and more often at higher levels).
This is the baseline I feel monsters are built for.
This is also my ideal game. No matter your archetype, you will deal comparable damage. If you give up a shield, you gain an appropriate damage bonus. This might be upping the damage die to d12 (which really is 2 less AC for 2 more damage). It might mean slightly more than that. It does not mean upping your damage maximum by 10 and getting pretty frequent bonus attacks.
If you are a frail combatant you are compensated. Either by getting relatively few big-punch actions (ie spells), or getting more damage (to explain why the party lets in a weak chain; ie rogues)
Fighting with a sickle, two clubs, a halberd... it's mostly a fashion statement. Sure historically better weapons could give you a slight nod, but not so much that players feel they have to stick with only a few weapons. If a "good" weapon gives you a point extra damage over a "cool" weapon, that's enough to flag real life. Much more than that, and you're asking cool concepts to sacrifice basic utility just for show.
[/sblock]This is all about balance across combat archetypes. As a starting pont damage should be comparable. A small concession to weapon "realism" is OK, but mostly it's fashion. (So the contrast between d4 daggers and d12 axes is implicity criticised.) Frail combatants get various forms of spike damage to compensate (wizards, rogues, etc).
There is no mention that wizards and rogues might get Charm Person instead of damage, but that can easily be factored into the point being made. The focus, in any event, is on "the fighting man", who does not get those sorts of options.
[sblock]
Problem #1 is, any group of reasonably experienced D&D gamers create characters with MUCH more damage than that.
The 5th edition PHB is MUCH more generous with various goodies that allow PCs to run circles around monsters and play with them.
<snip>
Problem #1 means that in any game with feats, multiclassing and magic items monsters (especially at high levels) stop working as listed, requiring DMs to tweak them or outright replace them. I'm sick and tired of not being able to just pull out a stock monster and use it as-is with zero prep, just because my players aren't newbie carebears that are content with not using the options in the PHB!
[/sblock]Mechanically optimised PCs do much more than that "fighting man" baseline, which makes life hard for the GM wanting to use monsters out of the books.
[sblock]
Problem #2 is, there exists far too many archetypes that can't do much more damage than that.
<snip>
Problem #2 means that loads of cool archetypes gets thrown by the wayside simply because it is no fun to be half as effective as the other guy, and some notion of "realism" told the designers only some archetypes get to be effective. Guy with greatsword, okay. Gal with throwing knives, fuggedaboudit.
<snip>
Even if we say "no feats" the problems do not disappear.
Warlocks and Sorcerers can do MUCH more damage (than 1d8+5 per attack, and one attack per tier).
I'm not talking about area attacks or save-or-suck spells. Those are, after all, quite limited in numbers.
I'm talking about Eldritch Blast. (For instance, limit Agonizing Blast to 30 ft!) I'm talking about twinned Fire Bolt.
<snip>
The despairing realization is that feats are NEEDED for martials to keep up.
<snip>
The problem with "feats are needed" is of course that this leaves a lot of archetypes in the dust. .
[/sblock]Without feats, "martials" get overshadowed
in the damage dealing department. Which is, ostensibly, their main schtick. To point out that they're also overshadowed in the versatility department (most fighters don't get regular access to Charm Person) is only to add insult to injury!
And even with feats, some archetypes (eg knife throwers, it is asserted) can't get out of those shadows, because there are no feats (it is asserted) to buff their damage.
The upshot (it is asserted) is that you can either use feats, causing (i) GM headaches in relation to monsters not keeping up and (ii) crowding out a whole lot of archetypes that should, in principle, be viable in a FRPG; or you can not use feats, leaving martial PCs overshadowed by casters
even on their home turf of dealing damage.
Nowhere in that post is there an assertion that "DPR is king". There is a
premise that DPR is the main thing a martial PC brings to the table. Now maybe that's not true; but you can't show it's not true by talking about how great a Charm Person spell can be!