Can anyone envision a scenario in which Tom would be killed?
For example,let's say when Tom is offered the job in Vegas,he takes it. Would Mike see this as a betrayal or even as a possible liability in the event that Hagen got caught up in something,and was pressured to flip?

On the other hand,what if after a few more years under Mike's rule,Tom can no longer live with his own complicity in so many heinous acts(the killing of the innocent hooker,the murder of Fredo,to name just two)that he decides to retire from the Corleone business and go into his own law practice.

Of course there are a lot of possibilities for Tom,but the bottom line is,would there be any justification in Mike's eyes to warrant getting rid of him.