There is evidence that it can be done. Evidence that a team can rebuild on the fly without performances and results suffering. That evidence has a name: Bayern Munich.
Bayern has managed the difficult trick of transitioning between generations without hurtling into the gaping chasm that separates them. Because that’s what tends to happen. Teams hang on to one generation of players for slightly too long. And with their successors either unaccustomed to the team or not yet recruited at all, the club slips into that gap. The veterans are reluctantly ushered out the door, and the new players trickle in.