But if the community reacts like this then you didn't really solve a problem for them. At least they didn't see it this way.
Perhaps a more apt analogy: you invent a better water filtering system and provide it to the world for free.
The community immediately starts using it as the benefits are undeniable, but now the community needs someone to do maintenance on their new filter system and you are the only one with the required expertise.
Should they "sponsor" you or is it fair of them to expect you to provide them support for free?
I don't necessarily think it is fair, but my guess is that even in your example, the inventor is unlikely to get paid very much by the community unless they had a maintenance agreement worked out in advance. They might be able to get some funding through something like the Nobel prize or Gates foundation.
Like the author of the article, I've observed that if you give a gift, it's very hard to charge for it after it’s been accepted. Whether this is innate to human psychology or caused by social constructs, I don't know, but it basically feels like a law of the universe.
Perhaps a more apt analogy: you invent a better water filtering system and provide it to the world for free.
The community immediately starts using it as the benefits are undeniable, but now the community needs someone to do maintenance on their new filter system and you are the only one with the required expertise.
Should they "sponsor" you or is it fair of them to expect you to provide them support for free?