> What firms are bringing in billions licensing or selling free software?

I work for SUSE, which is a free software company. Red Hat is another, as you mentioned. I found a list on Wikipedia[1] which has quite a few entries (though quite a few of those companies either no longer exist or were bought out by companies that don't exclusively work on free software).

> You can sell truly free software but almost nobody will buy it w/ you being super-niche in revenue.

That depends on your business model. The SUSE (and Red Hat) business model is to sell you a complete operating system which you are guaranteed to have support for. This is paid for by license costs for the base system and "modules" which are other pieces of software. If a user decides to install software which they didn't pay for, we don't support such a configuration if it breaks. Support in this case is not just support in setting up the system, it's also security updates and bug fixes (which are sometimes written by us and contributed back to the community). This sort of business model allows you to sell completely free software, because you're not selling the actual software you're selling licenses and support.

> My concept is to give you all the freedoms except for free distribution for a given project.

That would then be considered proprietary software in the strict sense of the word. It's better than nothing, but you have no practical freedom in that case because you cannot share your improvements to create a community -- one of the goals of the free software movement. The main thing to know is that free software is meant to mean that you cannot become entirely dependent on a company to support you. If you don't have the freedom to distribute modified and unmodified copies then you're (practically) at the mercy of the company that gave you the software.

> Seriously, as I'm trying to see how close proprietary, shared source can get to FOSS without loosing the "sustainable, cash flow" part.

Personally, I would never buy such software. I understand why it seems to be valuable to you to remove the free distribution freedoms of your users, but I don't agree with the logic. The problem is that you're still trying to "just sell the damn code", which doesn't guarantee you revenue with free software licenses (you can still sell it, but it's possible for a user to share the code with others without you knowing about it). Now, it's not very likely that many users would actually share the code (unfortunately), but it is possible. So, now you have to ask the question "what should I be selling". If you sell support (clients pay for you to develop new features for them, providing security fixes, bug fixes, etc) then you can make money selling completely free software. If you're scared of someone making money from your code, make it GPL and then you can take their changes back into your software.

Free software and proprietary software have only one difference which is how their distributed. Proprietary software is distributed in binary form only. Free software is usually distributed in binary and source form, but you can also distribute it in binary form with a link to where the source code is (and you can make it only be available to your customers -- that's still free software).

[1]: https://en.wikipedia.org/wiki/Category:Free_software_compani...