Hate to share from the site we definitely don’t think about anymore, but I think this is too interesting to miss. If true, it’s a big insight into the design of the game. All credit to that OP of course.
Summary is that WotC’s balancing decisions seem to make sense if they balance the classes like they balance monsters, using max damage output over a three-round fight. Basically they overvalue that, especially for certain nova classes (the OP suggests those classes are Fighter/Wizard/Sorcerer) and undervalue utility.
TLDR. WoTC seems to value Single Target Guaranteed DPR in a Nova over 3 rounds, and balances the game around that not too dissimilar to how they calculate the power of CR. And that seems to reflect every design decision and choice they have made when viewed this way, and what they gauge class power around. The core resource management of the game is about novaing now or later, and how can classes recover their novas.
Based on the way they’ve reigned in nova damage with 1D&D but have left utility spells basically untouched, I think the theory has merit.
The deficiency is in the monster building rules in the DMG. They haven’t been updated in almost ten years and it shows. For example, like you say, Druids and Clerics are ridiculously good classes, but they look “fine” because they’re not top damage dealers.
Those rules haven’t been updated for us since 2014. Meanwhile, WotC devs say that they’ve been regularly updating the tools they use to create new monsters and now, for example, take crowd control effects into account by translating the value of a CC into “effective damage” under the theory that “1 damage out” is roughly the equivalent to “1 damage in”.
…we didn’t get any of those improvements over the last 10 years. We’re still using rules set down in 2014 to make monsters.