Given the tremendous span of possibilities branching out from that point in young Picard's life, Q would've had his selection of what specific timeline to drop Picard-Prime into to demonstrate how it affected him down the line. Given his promise that no one else would be affected by Picard's change to history, he could've easily picked the one that most closely resembled the Prime timeline, even if it was a statistically unlikely or multiversally rare chain of events, without actively intervening and staging the situation artificially (though given Q's deal, creating a simulated history versus picking one out from a practically unlimited pool that fit his needs could be six of one and a half dozen of the other).
