Think you have a point there - it can also be seen as an ideal situation for clubs, as players can be motivated to perform to impress potential suitors.
We will see it more and more of it because the transfers are so high, even for average players. More and more players going into the final year of the contract will run them down, because no club will want to pay the amount demanded... in the next 5-10 years, it will become usual. Agents will have to find more creative ways of acquiring their pound of flesh.