That's how it used to work. That's 1990s thinking back when people would do these things purely out of love, and when those using it were hackers or ramen-noodel eating entrepreneurs.
Now huge corporations are using open-source tools, and some huge corporations have been built with open-source tools. Where would Google be without Python? Where would Facebook be without PHP? Where would Twitter have gone without Ruby?
That's why having an official method for giving back is important. Node has shown tremendous leadership here in setting up an NPM corporation (https://www.npmjs.com/about) that makes it easy for corporate concerns to donate without accounting concerns: Writing personal cheques to people to "donate" is out of the question. Giving to a foundation is noble. Paying for a support contract is reasonable. The difference might seem superficial, but it's important.
> I'll be targeting a niche group who are actually grateful for free tools...
There's nothing wrong with finding your own niche and doing it out of love and passion. That you're able to do this is great, but some need to concern themselves with how to make a stable, sustainable living that's not predicated on having a large amount of money saved up.