I can largely agree with that. And, yes, I do believe you hit the nail on the head.
As far as getting what I want, I suppose, you could argue that I already have. After all, 3pp have all sorts of social combat mechanics for 5e. There's a veritable shopping list of different systems, so, at the end of the day, it really is on me to simply adopt one of those and use them. I have already done so for exploration in my Spelljammer game, for example, to very good effect. And, of course, there's things like Level Up and the small mountain of material there that could certainly be adapted.
From free fanmade stuff, all the way to highly professional polished stuff. I'm really spoiled for choice. I mean, I was just perusing the other day an adaptation of Blades in the Dark's clock system for use in D&D 5e. There really are a small mountain of options out there.
It would just be nice if some of those actually made their way into the DMG so I didn't have to try to convince my bloody players that stuff that doesn't necessarily have the WotC seal of approval on it is perfectly fine to use in the game.

But that's a separate issue.