The second part of this logic is quite apparent: Assuming AI is game changing, early adopters will see an initial advantage, but in the long run everyone will have to use AI or no longer be competitive.
But the LTV (remember, for the sake of exploration we're assuming this is true) argues that value is always extracted as surplus (i.e. unpaid) labor from humans. So LTV would predict that if AI truly replaces humans we would ultimately see a decline in the surplus value that Capitalists extract, i.e. we would b faced with an economic crisis.
So LTV would predict that we would have either just as much or more hours of human labor happening or we would enter an economic crisis.