I think one of the problems is, that when new players are brought into the club, they tend to get in the team straight away. With no winning or earning the shirt.
The players who went on the training camp to Portugal and played in the pre-season friendlies, didn't do anything wrong enough to justify being dropped, so any feel-good factor gained from the team building exercise is lost and turned into a negative for those players that are cast aside.
The incoming players coast because they believe that the shirt is theirs and don't need to perform at the top of their ability to firstly win it and then keep it.