The veteran players Lombardi brought in were all willing to put up with, and thrive under Sutter. Once their influence and stability left, the core showed their soft underbellies and quit. Same thing they did under Murray, same thing they did under Stevens, and they never even bothered taking Desjardins seriously.
That being said, Terry Murray should have been let go after losing to San Jose. He had plateaued, and I suspect the only reason he was retained into the next year was that Sutter wasn't ready to get back into coaching yet.
Sutter had run his course as well, and a lot of players were unhappy under him. I don't know that keeping him around for another year would have been productive, but I suspect that Lombardi dug his heels in there not only for his friends sake, but also to keep the players in line. Meanwhile Robitaille was maneuvering behind him, negotiating an extension with Kopitar that Lombardi was hesitant to offer.
Quitting on Stevens is the one I really don't get. They got everything they wanted, but, just like it is easier to win once you have already won, its easier to quit once you have already quit without ramifications.