GTA VI by itself will make about 30 googles of money and then T2 stocks go to the moon. These people only react on a minute by minute basis, what can one expect?
Even T2's CEO doesn't dare tell Rockstar what to do (said it himself), they deliver everytime and make him all the money he wants.
But there are growing concerns with GTA VI due to almost complete change of the leadership at Rockstar (Dan Houser, producers, writers). I wouldn't bet money on VI being as big of a hit as V or even IV.
Even T2's CEO doesn't dare tell Rockstar what to do (said it himself), they deliver everytime and make him all the money he wants.