In the early years of Roman Abramovich's reign at Stamford Bridge the Blues were accused of buying success, with the Portuguese winning a Premier League and League Cup double in the first season of his first spell at the club.
But Mourinho argues that City's spending of more than 600 million pounds on players in the past six years has not received the same level of hatred, though he insists that the difference in treatment does not bother him.
"I'm not sure if it's because it's taken them six years to get to this stage while we won straight away and I don't care. I don't envy the fact that they have this kind of protection, or whichever word. It's the way it is. Teams with success, people tend not to like them, no?
"Financially, no, we can't compete. Back then it was a free world. There was no Financial Fair Play. If your club was a rich one, your owner a rich one, there were no rules. It was an open situation but times change.
"Many things people considered wrong 50 years ago are something very normal now."
Manuel Pellegrini's side has been in impressive form of late, having scored 68 goals this season, and the Blues boss accepts that Monday's opponents are skilled at shutting down other teams.
"I don't know if other teams have been scared of City, whether it's not so much that they don't attack them and more that they can't," Mourinho said. "Maybe they can't. I want to attack them, I can tell you that. But, after 10 minutes, people might say I'm not attacking. If I don't, it's because I can't."
Asked if Chelsea may have to concede the title for City this year, Mourinho was philosophical, arguing that second place would be a better finish than the team had planned.
"If we finished second doing the formation work, it's an acceleration of our process," he said. "It's good."