The problem is that often there isn’t even an easy way to give back sure there are donations but ironically for a non person entity making donation payments like this isn’t something that is possible because laws often don’t account for this model as the projects are often not registered charities or other statutory non for profit organizations.

When a company makes a payment to an individual or an incorporated entity that is not a donation. It’s very difficult to near impossible to even properly classify them which means you are at very serious risk of violating either employment laws or tax laws or both.

And a lot of projects that have a restrictive license don’t dual license or do it properly and don’t really support commercial channels.

So whilst it’s easy to blame freeloaders more often than not the project maintainers are at fault.