If they open sourced it, it would be less than a year before you'd start seeing "Azure Wolfram" and "AWS Wolfram" and so on and I can sort of understand why he might not want that to happen.
and using an AGPL licence, there would be no danger for them!
TimescaleDB has a good blog post about why they went this route[0]
I do think that perhaps we need to stop being so snooty about OSS vs open source, and recognise that companies with open source products are allowed to make a profit while preventing the big cloud providers from scalping them.
[0] https://blog.timescale.com/how-we-are-building-an-open-sourc...
The problem of big cloud providers ripping off OSS works is a new one, but it is explicitly allowed by OSS licenses - really not sure what a "good" solution is here, but personally I like the route TimescaleDB has gone down.
Please explain how/why FOSS is human birthright?
Making good software requires significant effort (both up-front and on-going) and being compensated for that effort is reasonable
Azure and AWS already have competing stacks to Wolfram, it is just various and sometimes incompatible hodgepodges of R, Python, Jupyter, and so on and so forth.
If Wolfram open source their stuff and people use it, it won't necessarily be a vindication. At the moment they have people who are willing to part with cash to get what they make. That's a definite vindication for anyone who makes things.
Really, with the kind of license proliferation that was going on due to every Tom and Harry that wanted to publish their own license, it was difficult to understand which license was really safe to use and which wasn't. FSF and OSI stepped in to bring some sanity to this situation by categorizing all the free and open source licenses by their permissiveness and restrictions. The majority of the open source development community adopted these licenses.
Any license that restricts making money would neither be considered a free license by FSF nor an open source license by OSI. The license could discourage making money without contributing back to the community and the GPL family of licenses do achieve that to some extent but they cannot outright restrict making money.
The OSD has its roots in Debian Free Software Guidelines which for a long time has been the community standard for what guarantees free software must provide. FSF's four freedoms of free software are also similar. OSD adopted Debian's guidelines to create the open source definition.
If a license does not allow us to run a software how we wish we lose freedom 0 to run the software how we wish. We lose the right to use the software for any field of endeavor. You might want to consider it "open source" because you can still see the source but widely accepted terms like "open source" do not get redefined so easily based on how some people feel about the term. The term's meaning still remains intact due to the meaning it holds for the vast majority of open source software developers.
There are other terms for source which is available but proprietary, such as "shared source".