The incentive is generally that people enjoy having their projects used, be that by commercial companies or otherwise.
That's the point!
GPL family of licenses would've made a difference in this aspect for libraries (because afair if you link to GPL code, you must be GPL). But for an app? You can use it, fork it, modify it... Just make sure you make your changes available under the same license. Seems very fair to me.
In practice, it does in many cases. Many companies have a blanket policy of avoiding these licences. But I agree that they make more sense for apps than libraries.
Then again I've seen companies publishing stuff on GitHub, when asked about the license; slapping GPLv3 on it but also forcing you to take a license with them for commercial use. Yea no, thanks. You just made a poison pill somehow even more lethal.
It really does. It stops it being used by people who need or want to use other licences. I believe it stops it being used on iOS and (probably) Android apps. The GPL world and the permissive licence worlds are walled off from each other in significant ways for lots of reasons.
Source: I maintain an app where I didn't choose and can't change the licence. And I come across code I can't touch almost every week.
I fully agree that (A)GPLv3 code effectively stops code from being used by many large companies (every place I’ve worked in the last decade has a near blanket policy on refusing to use code licensed that way except in very specific and exigent circumstances), but it isn’t necessarily true that app developers can’t use (or can’t choose to license) (A)GPL code in their iOS apps, provided they abide by the terms of the license.
Most developers won’t — or can’t — but the advent of dynamic linking of libraries in iOS, as well as the EU-mandated third-party app stores (which aren’t available outside the EU, but still), make the situation a lot more grey from the black and white stands the FSF attempted to take in the early 2010s. And to my knowledge there have been no legal challenges about the use of GPL code in iOS apps, so the issue is essentially unsettled.
That said, in most of the cases where I have seen iOS apps use GPL code, the full app source was available (and that may or may not fulfill the redistribution requirements but I’m not a lawyer and I’m not going to cosplay as one).
On Android, where full Google Play alternatives like F-Droid are available, plenty of GPLv3 apps exist, even if they aren’t available on Google Play.
But yes, when it comes to incorporating GPL code into a non-GPL app, that is much more difficult in the realm of mobile than it is for other types of applications.
Nevermind that Red Hat built a billion dollar business on top of GPL licensed code. Never mind the millions of embedded systems being sold with GPL code in them. Nevermind Google, Facebook, Netflix, etc., etc. all eating Microsoft's lunch a thousand times over using GPL code. Businesses better stay away! It's dangerous!
If there was no other choice, I may consider something LGPL or with the linking exception, but not until I had exhausted a search for something more permissive. To this day, I've never used GPL in any of my code, open source or closed. I've been writing code for 35 years daily.
Why? Do you also avoid libraries with an even number of consonants in the name?
