licence

Those that want to distribute or sell their proprietary modules along with the compiler cannot, and that is exactly Ciaran's point: a company cannot make a business of selling proprietary enhancements.

Not being able to go back to the business of selling enhanced version, you mean. Or selling any version at all, unless by selling you mean "asking money while at the same thing giving the same thing for free".

They can sell what they like as long as they adhere to the licensing: Red Hat seems to manage quite well doing just that. You'd think that being able to say "I am Monty!" and insisting that enough extra value is generated would be enough to differentiate Monty's outfit from other forks of MySQL, and Monty can still sell the software under the GPL. If his customers value that special edge that only Monty can provide, and if they're doing everything over the Web anyway, as long as they get the source code, no-one is violating the licence. And even if they ship actual software, if end-users are as apathetic as you make them out to be, they won't bother uploading the sources to the Internet, will they?

As I said, that's one of the problems created by copyleft licensing, which would never occur with permissive license.

You'll have to do better than that: if PostgreSQL was all owned by a single company - let's say it was Oracle - would the "open source" version still be under a permissive licence? I doubt it.

Nobody loses. End users are happy, because they can buy better product, that wouldn't exist with copyleft license, because noone would invest serious money into development of something they have to give away for free.

Yeah, that Linux thing: no-one's invested anything in it. Even now, people and organisations are investing time in the open source variants of MySQL, although I myself wonder why they bother, but that has nothing to do with the licence. To make such claims is just plain disingenuousness at its most blatant, especially given which site you're writing this on.

End-users do get the benefit of an improved product, potentially, disregarding the dog's breakfast that a lot of consumer electronics vendors seem to make when their code is exposed to public scrutiny, but end-users don't get the benefits around the code. This may seem unimportant to you, but claiming that it's absolutely unimportant is practically the same as the Bill Gates' jibe about "no-one wants the source code of their office suite": demonstrably untrue for, to take but one example, people whose native language is not in the list of wealthy, easily-milked markets supported by Mr Gates' proprietary software.

Yeah, you're right here. However, it's not possible to incorporate it back into the original project (in this case Mozilla), for reasons described above. Still, it's yet another problem caused by the copyleft license.

Yes, I am right and you know it, although that didn't stop you from making stuff up anyway. And it's only a "problem" for people who want to consume permissively licensed software. A "problem" which amounts to the whining often seen when people whose permissively licensed work suddenly ends up in a copyleft-licensed project: whining which is more or less equivalent to "I wrote one thing but I meant another". That these people then accuse copyleft licence users of "not respecting other people's wishes" just demonstrates the levels of hypocrisy involved.

You mean, like all the other proprietary projects listed here? [page showing list of source packages]

Do you expect us to go through those projects removing the ones that are not copyleft-licensed and then bask in the generosity of Apple? Well, looking at the list and choosing a few projects at random, it quickly becomes an issue of assessing (for us and for Apple) whether it's worth the bother of maintaining a proprietary fork.

Take something like python-dateutil, of which I have recent experience: sure, if Apple's employees/lawyers thought it worthwhile to maintain a proprietary version, they'd probably do so, but such work would be fairly unappealing and would not provide any economic or strategic advantage. Why not let the maintainer(s) do the time-consuming and thankless task of making sure such a piece of infrastructure just works? Throw a few patches over the wall every now and again, just to keep the local maintenance burden at a minimum (and to avoid having to patch numerous Python-based packages which depend on it).

In contrast, when you're in desperate need of a Web browser that you can control - noting that Safari is yet another vehicle for standards front-running - there is a real incentive to maintain a proprietary fork if you can. And when you can put many more developers on the fork than there are behind the original project, the incentive to work with that project diminishes.

Finally, given that Apple are quite content to use patents as a form of anticompetitive instrument, is it really so hard to believe that had WebKit been permissively licensed, Apple would not have taken the opportunity to freeze out competitors like Nokia by taking their derived version private? It would surely be cheaper than a bunch of patent lawyers.