From Bulpett, linked above:
Team A calling Team B in recent weeks to ask if it would give up assets A, B and C for Player A — and being told, "No" — does not a negotiation make. Rather it makes for a pretty quick and fruitless phone call.
The implication here, I think, is that Daryl Morey called Ainge, not the other way around, and basically asked for a handful of the Celts' best assets in return for Dwight.
E.g.
Daryl: "Danny, would you consider trading Marcus Smart, one of your Brooklyn picks, and Kelly Olynyk, plus Lee's expiring, for Dwight? You'd finally get that star you've been after!"
Danny: "Um, yeah, no, not a chance Daryl."
Sounds totally plausible.
But what also could've happened is Morey asked for two non-Nets 1sts and Ainge still could've flat out refused just as a routine negotiating tactic. Conversely, if Morey asked for Smart, Olynyk, and a Nets 1st that might also just be a routine tactic of overshooting. The fact that any talking happened is more important than what kind. Morey and Ainge negotiating must be like sharks mating. A slow, cautious dance of two predators wary of each other.
There's no way any other team is going to offer Houston even a
third of the value of Smart + Olynyk + Nets 1st. That's more than Orlando got for Howard at his
peak, lol. Two weeks of media-leaked posturing later, Ainge and Morey will probably settle on something, because there won't be better options for either -- and that includes doing nothing, which neither wants to do.

(Pictured, left to right: Ainge and Morey two weeks from now.)