Is the roleplay aspect of D&D gone, replaced by optimization?

[KorvinStarmast]

It's because talking about roleplaying often kind of sucks, but actually roleplaying is really fun.

Conversely, talking about optimization is fun, but (for players) it only relates to a tiny portion of the game (character creation and levelling).

That's a nice way to answer the OP. I'll be keeping that in my back pocket.

Except the main prompts the game does a good job of pushing are killing things to take their stuff

Hmm, the bulk of published material in the PHB is "look at all of these magical spells, here is what they do" when you get to a page count. Combat is given a detailed treatment, mechanically, in order that play follows an orderly and (reasonably rational) flow, and to allow for a certain amount of structure around which to create choices. The rest of the game follows the three steps in How To Play" in the PHB.

If you look at the published adventures, with few exceptions there are a variety of negotiating and bargaining scenarios provided for the NPCs, and some monsters, if one reads all of the material provided.

But one thing is for sure: treasure hunting is still a core feature. (Why take all of that risk exploring if there is not a great reward? Stick to fishing). The story telling is by its nature emergent: how we went about recovering that treasured scroll, or priceless vase, and all of the errors and successes we had along the way is the story. It's the journey that makes a difference.

Great example last night when the party (me DM) encountered evidence of a bear in a cave. Totem barbarian asked the party to stay back; the 10 min ritual was done, and barbarian moved foward and began to have a conversation with the bear. As it worked out, they fed the bear some iron rations (we treated it like 'here, have some doggy snacks' ) and the information the bear provided ended up being crucial: the evil duergar cleric they'd been looking for had recently been eaten ... by this bear. But it had lost its mate during that confrontation. When they were done, the barbarian and the bear shared a bear hug. And, the search for the duergar cleric was now completed.

Nobody knew anything like that was going to happen when we sat down to play last night.