As Cartman has highlighted, most of the 'key' players who have left over the last 3 years have been approaching the end of their contracts and therefore had the upper hand in any negotiations, whereas now, most of our 'key' players are at the opposite end of their contracts.
Ok, so we all know that "contracts aren't worth the paper they are written on" but it does put the club in a better negotiating position in each case.
So there is a difference this summer compared to previous summers but whether it has any tangible effect remains to be seen.