To me, perisic is a good example of how sometimes players let money get in the way of their own happiness. When Mourinho pushed to have him, Manchester United offered around 35-40 mil, while we asked 50. So it didn't go through.
I'm willing to bet that United would also offer more money to him than he earns here, probably at least 2 mil more. So had he made clear that he would go there for the same money he earns here, United could have raised their offer and he would be still rich, but also a Manchester United's player, like he wanted.
Now that Mourinho is not the red devils' coach anymore, there is no chance of this happening.