Well there’s https://gitcoin.co/

Not royalties, but dues at least.

A DAO structure would work well, but not many people seem to see it as viable.

Royalties should be based on % of revenue generated by a product where particular software is being used and distributed among contributors. You are conflating volunteering with internship. If a company recruits volunteers as software developers, this is a disguised internship and they'll get themselves liable. This is illegal in the UK.

and if the open source project generates no revenue?

Like, if Y is controlled by the Y foundation which is in part funded by Z company, Y foundation isnt really getting a direct revenue stream from the software - thats the thing about open source software, you dont have a say in how its used, and you cannot force payment.

I think your read of the law on what is or isnt an internship is a wee bit of a hot take, but IANAL, and certainly not a UK Labor Lawyer.

> and if the open source project generates no revenue?

For example 0.1% of 0 is 0 (https://en.wikipedia.org/wiki/Percentage)

Whoever gets the revenue from the software should be paying.

Regarding any constructs with foundations and other tax avoidance schemes, that's probably another topic.

So, basically, you're saying that if you make money from the software, you should be required to pay money to the copyright holders (aka, the developers).

At that point, what sets aside open source software from any other kind of software?