This is solid. The team is not going to leave as a whole as much as any business would abandon a healthy (or maybe not so healthy) customer relationship. I also think that people will leave the team for the same reason they'd leave a healthy employment relationship: startup opportunity, education, family, retirement, etc.
If the whole team does decide to move on, it's likely that the set of circumstances that would push a "packaged team" like this away would probably cause mass attrition with normal employees as well. Just today a friend of mine told me the 2 layers of management between him and the CEO quit on the same day, and he's feeling like he wants to quit now as well. So goes the pack.