Chelsea are in a long crisis that lasts since the past season and they are trying to end their crisis. They bought many young star players and I believe it is their plan very long term growth of the club. They want to build up a competitive squad for their club in next several seasons. A biggest problem in Chelsea latest season is they don't have stability for their coach position that causes of lot of chaos in the club.
Yeah... its true. relying too much on instant results in the football world is like a self destructive bomb for the club itself. Any coach needs their own adaptation period to a new club. It takes a longer time to truly figure out the winning formula and strategy for a coach. One of the best coaches who didn't get much of a chance was Rafael Benitez, as he only managed for 220 days before being replaced by Jose Mourinho.
Chelsea can seriously harm the club if they keep changing coaches because they're dissatisfied with the current coach's performance, especially when they've been in the job for less than a year.