Seems to me that the questions above assume a flagship state school mentality that already exists for most of the states in the U.S., but is non-existent for NY and MA.
Privates are too well embedded in those states. Example, when one thinks of the great universities in the states of Michigan and Ohio, the first reply, especially from residents of those states, are University of Michigan and Ohio State University. That's not what happens when asking about the states of NY and MA. In Massachusetts, the replies will begin with Harvard followed by MIT. Then there is Tufts, Brandeis, Boston University, Boston College, UMass, and more I am probably forgetting that will rank anywhere from 3-10 (not saying which will rank where). The advantage UMass has here is that is indeed the recognized state public institution.
In New York, it's the same thing. There are privates Cornell, Columbia, and NYU and then a group of 4-10 that will likely include University of Rochester, RIT, SU, SUNY Buffalo, and SUNY Stony Brook and others I am forgetting to include (again not saying where any of this group would rank in 4-10). The downside for UB here is that SUNY, for political reasons, prefers its 4 University Centers model. Whether one agrees or disagrees with that approach is immaterial. It is what it is. And since all of the political clout is in Albany, I don't see that changing any time soon.
But let's assume it does, and UB becomes the official premiere public institution in New York like UMass is in Massachusetts. Then you have all the hurdles that Scooch outlined in his post. The state flagship mentality is built over decades within the core heart of the state. And that is on the academic side of the equation. On the athletics side they have an even tougher task since SU has the spot sewn up quite tight.
So I don't see it doing them much good, even if we assume that at some point UB is allowed by the SUNY system to brand itself as the premiere flagship of New York, SUNY actually invests huge in athletics, and then builds an athletic reputation that nearly equals SU's.
Cheers,
Neil