"Firefox is already GPL'ed, such a license change would violate that (along with many libraries it depends on also being GPL'ed). This is not possible."

I understand that, and I accept it as a problem. I only used LibreOffice and Gimp as examples of large projects that have issues, I should have made it clear I wasn't suggesting they convert to a different licensing model. Clearly, under GPL-type licensing converting to another licensing structure would be nigh on impossible. Nevertheless, that they can't raises issues which I'll mention.

My suggestion arose out of what I perceive as a problem with some open-source projects. Let's take a look:

There are many open-source and commercial programs that are now effectively abandoned-ware but given the right incentive some could be resurrected and turned into useful products. View this another way: a lot of human effort has gone into making both commercial and open-source programs and letting all that effort go to waste doesn't make sense if there's a viable alternative. That said, we know that finding the right 'incentive' has proved difficult and elusive.

Both developers of open-source and commercial programs often have good reasons for stopping further development of their programs. For open-source developers often the incentive wains and having to continually maintain a program without financial reward turns into drudgery. Likewise, a developer of a small commercial program will stop further development for various reasons some of which are similar to those of open-source developers.

I'll give you an example, I still use a Windows file management utility produced by an individual developer which I purchased about 15 years ago and unfortunately he has ceased further development of the program. Trouble is that program is for my purposes the best-of-class for reasons I can't dwell upon here but it needs updating to a Unicode base (I still use it regularly but it throws errors with filenames containing non-ASCII characters).

I've exchanged emails with the developer and I fully understand why he's ceased development (he has good reasons). A very similar situation exists with some open-source developers, they've ceased development of their programs for similar reasons. Unfortunately, in both instance users are left with abandoned-ware.

With both open-source and proprietary software, many programmers still hold residual vested interests in their code even through they've ceased developing it. Often, this revolves around the fact that they don't want others to benefit financially at their expense even though for various reasons it's difficult for them to actually profit directly. (Let's face it, that's understandable—it's pretty much human nature.)

The result is an impasse: open-source code stagnates in the hope others will continue its development, which may or may not happen (and often it doesn't). Similarly, commercial code is neglected and or goes into limbo. And more often than not it ends up dead and abandoned.

Clearly, the gulf between open-source/GPL and proprietary software licensing is not only wide but also contentious. In respect of these problems I've no better solution than anyone else except to say that I believe there ought to be some better system or mechanism whereby open-source developers can at least receive some renumeration for their efforts. Providing an additional financial incentive to developers would also significantly benefit users.

Obviously—given current licensing arrangements—the halfway measure I've suggested would only be applicable to new projects, and that alone poses additional problems. The fact remains we need to find some way of providing better incentives to developers so as to ensure important open-source projects are developed in a timely and professional way as is so for the best commercial software. By that, I'm certainly not saying that all open-source projects aren't being developed in a professional manner as clearly many are. But then there are many that are struggling. How we best deal with them remains open.