He provides the source for people to see in the first place. Assuming there are no patents involved, that makes anyone free to re-implement ideas there, which is a risk for him, but nice for everyone who wants to see source code of stuff they use (I do). Then, when it turns out he no longer needs the product, it's free for everyone. If people don't find it worth the money but do want to use it and hack on it, they're free to do so, with or without him. So he's not asking to work together or for help in later years, he's giving the opportunity to use it after he stopped doing so himself.