I think you might have misunderstood my argument. My main argument is that the money from selling proprietary licenses also pays lots of developers to work on important things, which they wouldn't (often couldn't) do if they weren't getting paid for it. So the users of the software are better off because the developers were able to do important work and get paid for it. And that was only possible because the vendor could be highly confident of getting enough return on its investment to justify paying those developers. And the vendor could only get such a return on its investment because it's selling proprietary licenses, as opposed to selling an auxiliary service (which often leads to misaligned incentives for end-user software) or begging for donations.

Don't forget that (and this has been mentioned four times now in this thread) you can sell open source software. No need to beg for donations. Charge for the software and for the source code.

But then as soon as a paying customer exercises freedom 2 and helps their neighbors by redistributing the software on the Internet, the vendor is most likely screwed. Particularly if they developed a great piece of end-user software that doesn't need support, training, hosting, or any other service to go with it.

Has this ever been shown to happen in practice? The vendor is the only one who can provide a guarantee that the distribution is genuine (i.e. not tampered with), provide timely updates, security notices, etc.

Your premise is wrong: there is nothing unethical about closed-source software. In 99% of the cases users want great software, great customer support and don't care about the source. If they really do, they can often sign an NDA and buy it. And that's fair. Free market doesn't need a pseudo-ethical middle-man.

I think you might have replied to the wrong comment, because this response makes no sense. ddevault said:

> I reject any argument which justifies behavior because it makes someone money that they otherwise might not. Captalism does not justify a lack of ethics.

ddevault's point is that the mere fact that doing P makes someone money is irrelevant to whether it's ethically okay to do P. ddevault does not say whether closed source software is unethical or not (in this comment), and so your "premise" does not exist here.

Furthermore, you go on to make exactly the mistake ddevault is complaining about: "there is nothing unethical about closed-source software." Why? Because "[the customers are willing to pay for it]". The fact that there are people willing to pay for something is irrelevant; the fact that there's a market for hitmen doesn't make that acceptable either.