Chelsea and Internazionale have a lot in common. Both enjoyed success under Jose Mourinho, both have been through managers like there's no tomorrow in the immediate aftermath of Jose Mourinho.
Chelsea are on their seventh boss since Mourinho left them five years ago, Inter are up to four in less than two years. Both clubs are burdened by the weight of Mourinho's signings, invariably experienced players at or near their peak when signed and therefore pretty costly. There's no legacy planning and Mourinho is very adept at picking the right time to move on, the fans still in awe and memories of glory days fresh in the mind. The problem arises a short time later when those players at or near their peak suddenly pass it and the incumbent coach finds a squad not fit for the job in hand. Mourinho's teams all get old together. It's as if he arrives at a club already knowing how long he's going to be around and builds a team that will last that long and not a great deal longer.
His attitude to his players also works against future coaches. By protecting his players from all external criticism - his antics with the media and on the touchline look more like the work of a Machivellian schemer than pure coincidence - he helps inculcate a culture where they are immune to everything, be that honest appraisal or new ideas.
It's also no coincidence that Inter and Chelsea both have notoriously trigger-happy chairmen, but even as far back as the 1930s when Fulham fired Jimmy Hogan after 31 days, players have had their say over managers who try to get them to do things they don't see as worthwhile. And who is easier to sack; one manager or 25 players? Moratti and Abramovich have been culpable of facilitating this trait of Mourinho.
It's like salting the earth behind you as you leave the farm. Nobody will be able to grow anything there and your reputation as a master farmer will remain intact for generations. Mourinho seals his legacy by getting to decide that his successors will not be able to emulate him.