The only domain where I have seen this is with commercial scientific software that is designed to be run on supercomputers. This is mostly due to the difficulty of producing high performance binaries that work with the MPI implementation.

One interesting implication is that since people can view and modify the source code, patches and modifications to the software are shared.

This has always lead me to wonder if a diff file violates copyright as it includes some of the original source as context.

I'm not a lawyer but this reminds me of how game mods are shared for old games. They are shared at patch files to avoid sharing the copyrighted original binary/rom file.

My understanding is that use a patch file as long as your patch doesn't include any copyrighted material it is fair to share.

A patch file does not necessarily have any of the original code, just the location info and the new value.

This is still how custom themes for the switch are distributed since the menu file is considered copyrighted they distribute a file and a tool you can use to apply the file to the menu file on your system.

YLLMV (Your Local Legislation May Vary), but reverse engineering and subsequent modifications are completely legal here, if they're more for compatibility than competition.

I also wish everybody would install adblock on all their devices etc.

It's one of those problems that are solved only at the individual level but because of that are not going to be solved at all.

This was a shift in viewpoint -- earlier in the life of computers, the hardware was seen as the really valuable part of a computer. So companies would provide the source code because that was simpler (the software was "just a toy"). But then software became the valuable component, and so businesses (as is a recurring theme in capitalism) didn't want to give away something that might be potentially profitable. And so we now have proprietary software. This shift in viewpoint by users was an intentional move, pushed by soon-to-be proprietary software businesses.

I think you may have missed my point. I want businesses to profit off of their software... I just also want them to provide customers with the sources used to produce the software they just paid for.

Copyright law can still apply. Just because I have your sources doesn't mean I can go and use them in my own software, or re-implement your patented algorithm.

"But how can I be sure that my customer isn't stealing my work?"

Well, ask someone to look at the source code they provide to their customers. Remember, we're in an imaginary world where source-included is the normal way to sell software, and anyone peddling binary blobs is seen as shady.

You having the sources does not change the incentive of the software’s creator. The unwanted functionality (which the software creator is pressured to include) will instead be put in:

1. Obfuscated code. This is a classic, employed back in the day when raw machine code wasn’t quite as much of a barrier like it is nowadays. Less common now since its importance has lessened, but still ever-present, and could be re-employed instantly.

2. The very design of the software. For instance, the software might require a phone number for every user, and this is baked in at the very fundamental design level, making it impractical to change. Other design choices might encourage you to share your contact lists, for say, backups, and your data is now leaked.

3. The software is merely a collection stubs calling a cloud service. Very common now with so-called "apps" for phones. This design has come to its pinnacle with “web page apps”, where only the front-facing UI portion sits on the user‘s control, and the rest runs remotely.

This is why “shared source” and the like is not enough. The end user must have the practical ability to, reasonably easily change the software, either by themselves or by hiring anyone they like and/or trust to do it for them.

Kinda how commercial game engines often came with the source code. Not open source, heavily restricted with license, but available for the user (licensee) to look at and make modifications to it required.

I find it interesting you are harping on an aside I made in the middle of an accurate (though very abdriged) description of the history of proprietary software.

But, to your point -- yes, companies can do altruistic things. That doesn't mean they always do altruistic things, nor does it mean that they tend to do altruistic things. This should not be surprising -- companies are designed to maximise profit and altruism is rarely as profitable as other avenues. Companies which contribute to or sell free software are in the overwhelming minority today, let alone 30 years ago.

I didn't mention socialism, nor redistribution of assets. More importantly though, if you feel the need to protect the concept of capitalism whenever there is even the hint of criticism, then you should take a page out of Hamlet -- "the lady doth protest too much, methinks".

Also, free software isn't socialist. If you feel the need to tie to it a political ideology, it's much closer to anarchism.