When I was younger, I would have been annoyed at this remark because it detracts from the ideological purity of FOSS. Now that I'm older, I laugh at its naïveté. $megacorp wouldn't pay you. The junior engineer at $megacorp who pulled in your library wouldn't even have read the license. And you as a small FOSS engineer wouldn't have the legal clout to make them pay. You wouldn't even know they were using your library.

But in principle I agree that it would behoove profitable companies who benefit from FOSS to either pay or contribute.

They would pay, once their product depends on your work.

Would they? Their products depends on the work of thousands of FOSS contributions. And historically, the vast majority of companies haven't contributed or paid. All they've done is take. There have been numerous cases of GPL violations and other misappropriations of licenses. I don't see why a "Pay me $1000"-clause would be any different.

Was at a talk by the curl maintainer a while back, he has a stack of emails from entitled companies that expect him to work for free. It's mind boggling.

There are companies that will pay because not everybody is mental. With that money you can enforce the license for the others. It doesn't have to be perfect.

It's not open source anymore once you add this; open source is defined as having equal terms for everyone.

That said, a few entities are advocating for something like this, e.g. Bruce Perens with Post Open (https://postopen.org) or FUTO with "source first" (https://www.futo.org/about/futo-statement-on-opensource/).

A big hangup with all of this is, who is "us"? Whom do you owe money to?

The original author? What if I end up forking the software without the original authors involved, am I going to do it for free with all the proceeds going to people who aren't working on it anymore?

Or all future contributors? Using which formula to divvy up that money? Lines of code, useful bug reports written, number of tasks triaged, number of tasks resolved, documentation authored, users supported - what determines the relative amount of your contribution? Who receives the payment(s) from $megacorp, can they be trusted to redistribute it among contributors? What happens when the original maintainer / payment receiver steps back or scales back their contributions? How to avoid the divvy-up metric being gamed by people who care more about the money than the quality of the software?

Yes, it's possible; no, "just add to the license" doesn't cut it. This is a much bigger question. How you answer these questions determines whether your project even preserves open source's main (user-side) benefit of forkability.

There are companies that already did this, I don't know why you try to complicate it.

Even comercial software can be open source.

Also "everybody" does not have to include companies. Sice when are companies people?