You're greatly oversimplifying the situation. While John III Sobieski was hailed as a savior of Christendom, his choice in allying with the Austrian Habsburgs set him as the junior partner in the alliance. He had no choice but to save Vienna, because he was engaged in war against the Ottoman, and he had no partners willing to ally with him except Austria. Tellingly, following the success in Vienna he had no lasting political nor territorial gains.

As far as the possibility of a lasting alliance with the Ottomans, you completely miss the long decline of the government of the Commonwealth. In a period of centralization, the Commonwealth tended to decentralize. This put much more power in the nobles (szlachta), which tended to elect weak kings such as the French Henri de Valois. Heck, the szlachta elected Vasa kings that brought the Commonwealth into direct conflict against Sweden, and heralded a definitive end to a previous period of sustained growth and prosperity.

With such tendency to shoot themselves in the foot, it's hard to imagine how the Commonwealth could have avoided the partition altogether.

I can't speak to European views of the PLC but I would push back a bit against European conclusions about the decline of the Ottoman empire as that's only something that's clear with hindsight. It would not have been obvious, and we have statements to the effect that it was not obvious, that the Ottomans had ceased to be a threat. Moreover they attempted and conceivably could have reformed the empire in such a way as to reach parity or superiority with their European rivals. We now know that the Battle of Vienna would be the last Ottoman assault on that city but whatever their thoughts about European superiority or Ottoman decline there was no way for a contemporary European observer to know in 1683 that that would be the case. Moreover the declining Ottoman threat was brought about in large part because of the balance of power between the Ottomans and neighbouring Persia, with whom the Ottomans also fought a succession of quite draining wars between the 16th and 19th century.

John Darwin's After Tamerlane gives a great analysis of the respective balance of power between Europe states and the rest of the Eurasian states in this period.