while superficially similar, I think the situation is nothing like ours
bosh and lebron had a lot more leverage than carmelo. With the new CBA, there's a risk that he either can't leave anymore (if a franchise tag is introduced), or that he'll get significantly less money, tens of millions etc.
so carmelo had all the incentives to announce his intentions to leave, so he can light a fire under NY's ass to try to get him now. Bosh
and Lebron had no reason to do the same.
Carmelo will go to NY one way or another, but he'll much rather do it now, via S&T, even if that means NY will lose some assets. From NY's perspective, they also know they'll get him, potentially for free in the summer, so they are in no hurry. However, by spreading the rumour that he might sign an extension in Denver, carmelo is trying to create some urgency on their part.
I'm also not convinced that Denver is getting THAT much in return. If they could trade those players into draft picks later, that'd be a fantastic move. If they decide to keep them all and move forward with their new core, they'll just turn into Indiana, a .500 or so team that's not good enough to make waves and not bad enough to get good picks. Felton, Laywson, Gallinary, Chandler and Nene are good complimentary pieces, but they're not winnining a playoff series with that alone ...