Rather than talk about symantics, we should consider only the reality. Anyone who starts using free software as a basis and builds on top of the free software owns nothing, except perhaps the kudos for the good work on their app. If they obey the opensource license, they have to distribute that app for free. Free beer abounds. That is the reality. Plenty of free beer for everyone. No one can meter the free beer nor enforce a payment from anyone who uses it. But someone does have to refill the barrel occasionally or no one gets anything at all after their first few drinks.
There are a lot of podcasts these days with people making big money from donations to keep the podcast going. Generally, if the value is there people will donate.
Why not do the same for opensource software? The biggest challenge is centralizing the payment method in a credible way and encouraging people to pay for their apps. I will not sign up, create a login, get a password, register my credit card, and make a software purchase/donation for only one app, and do the same in twenty different websites, to get twenty different apps. No way. But I might sign up, create a login, get a password, register my credit card, and make several dozen software purchase/donations in the same website over time, just like I do making purchases from Amazon. Such an app store should have an option to download either the free or the paid version, with both versions being the same. The culture there would be to encourage people to pay for their apps. Other than that, it would work just like the Android Play Store. The store could even give out the source code for free and charge if the customer wants the compiled version.
A lot of Linux apps are just pretty lame. But with proper monitization, a lot of very good apps could be distributed through such a store. Talented app writers need to be paid if we want them to work on much needed apps. People will donate if they are receiving value. And the more opensource apps exist, the fewer closed apps can exist as their code might infringe on opensource licenses.
With a little effort and a change in culture in how people think about opensource software, a booming industry can develop. Linus Tarvolds didn’t start Linux because he wanted to charge everyone to use Linux. He didn’t even ask for donations, and his talents are known world wide. Hi isn’t exactly starving either.
Any serious linux, opensource code writer who wants to get paid writing opensource apps should start the first credible Linux app Store and host as many good apps there as you can. Most people don’t mind paying a reasonable amount for apps they find valuable and might even donate larger amounts if they are really impressed. A five dollar app times one-thousand paid users per month is sixty thousand dollars per year. Four apps like that and you’re making just shy of a quarter of a million dollars per year.