Towards the end of the story Michael is building Rocco Lampone Regime and possibly Al Neri as well (although this is a guess) we can assume Michael was developing his own loyalist in the Family. He had probably started with placing roots in Arizona and getting a foothold in Vegas.

Its far to say Michael would have been able to survive on the West coast and leave the NY rackets in the same way of GF2 but it wouldn't have been on his own accord.
Of Course, Michael's power is secured until the end of GF1 and expand inbetween GF1 and GF2 but I think he would have survived.

@Turnbull
It hasn't been an official "co-Donship" but there have been several powersharing dynamics in history (Paul Ricca/Tony Accardo, William Tocco/Joe Zerilli, Tom Gagliano/Tommy Lucchese etc) Its not out of them realm of possibility that Clemenza and Tessio could have worked together. Tessio surely could be negotiated with But I don't think Clemenza truely wanted to seperate