Inter and RM were not poisoned chalices, he has never been a long term manager.
Moratti has seen off quite a few managers and tell me one manager who has managed to stay long-term at RM these past few years?
Definition of Long-Term: 5 years or more
Also I don't get how you can say Mourinho is not a long-term manager when he has effectively never been at a club for more than 2-3 seasons for a variety of reasons. He was sacked from Chelsea otherwise he would still have stayed. He left Inter cos he hated Italy. He left Porto to join a better club in Chelsea. Similarily he left Leira to joing a better club in Porto