Putin is also better then nearly all the Soviet leaders(Gorby's the exception ).
But if the Soviet Union didn't break up in 1991, it would be Gorby who would probably stay in power for another 5 years or so, and then maybe he will be able to hand over his position to a like-minded successor.
How do you propose this ever be accomplished, though? The USSR was doomed just as much by its multinational nature as its economy. Once restrictions on free speech and national expression were torn down, the multitude of ethnic issues that the Union had attempted to paper over came to the fore.
The question wasn't about whether this was possible or not.
But, if we are speaking about the possibility to preserve the non-Communist USSR: it depended on many factors, of which one of the most significant, and typically underestimated, was Soviet administrative division structure (it was probably too late to change this by 1991 and even by 1985, though). It's not a coincidence that the USSR broke up precisely along the administrative borders drawn by the Soviet leadership, which in many cases were very different from ethnic borders. It's also not a coincidence that another 2 multi-ethnic "federations" modeled after the USSR (Yugoslavia and Czechoslovakia) also broke up, and also precisely along the pre-existing subnational borders (and in Yugoslavia these borders were also very different from actual ethnic borders). At the same time, multi-ethnic Bosnia and Herzegovina managed to survive, despite less than half of it's population were Bosniaks, despite the conflict there was far more severe than most of the Soviet ethnic conflicts and despite separatists received support from adjacent countries larger and more powerful than it. In Africa, you can see ethnic tensions in almost any country, but 2 out of the 3 most successful secessionist movements, Eritrea and Somaliland, formed along the former colonial, rather than ethnic, borders. And in Latin America most of the new post-colonial nations were created on a basis of the former colonial viceroyalties.
We can't say for sure how much chances to survive the Soviet Union had. We can say for sure, though, that being multi-ethnic, and even having severe ethnic tensions, doesn't yet mean that the country is doomed.