out of those though:
Simon Shaw & Tom Palmer wanted to take the French cash while they had an opportunity (can't blame them)
George Skivington didn't he leave because he wasn't getting enough games? Can't remember
Thibaud Flament - needed to be in France to play for France
James Cannon - always a 4th choice
Matt Symons - had missed most of a season with injury, Wasps might have had doubts as to his longer term fitness
Charlie Matthews - never really cemented his place even though he always looked decent when he played
Will Rowlands - needed to be in wales to play for Wales
out of that 8, I don't think Wasps could do much about 4 of them, and they probably weren't that bothered about at least 2 others.
However, you could also add Levi Douglas, Lash Jaiani & the other guy signed from a French club Edwards, can't remember his first name, don't think he ever played a game. But I would say none of those were guys Wasps would probably break the bank to keep.