Despite the news, Palm said it would continue developing products based on current versions of Palm OS. Without paying royalties to PalmSource, newer versions of Palm OS will not be available to Palm.
It'll be more than five months before the royalty payments cease, leaving plenty of time to at least open up talks between the two companies. If they don't come to some form of agreement, we may see Palm switching to an entirely new OS, with some speculating they may move to Microsoft. While I doubt that would happen, it does make you think that Palm may lose users over the potential future lack of support.