That's possible, but if you'll allow a MS skeptic to play devil's advocate for a moment...
If Microsoft actually did change their policy towards open source for the better, what actions would we reasonably expect from them? What they'd done so far, I believe, could easily be construed in that light as well. Consider this possible interpretation:
(1) GitHub, the cornerstone of open source, is on the brink of having to shut down. Microsoft puts their money while their mouth is, and purchases them so they can keep the platform alive and well, and out of the clutches of anti-OSS companies that would bring it harm.
(2) In order to bridge the gap between their software and Linux, they open source their entire .NET platform, and begin building Azure on Linux. They regard Linux and OSS as legitimate and worthy competitors to their software, so they choose to level the playing field; now developers don't have to choose between Windows and Linux, but can build for both, meaning that users can decide more readily between Microsoft and Linux products.
(3) To further make it easier for developers to develop for either operating system, Microsoft creates Windows Subsystem for Linux. There were plenty of options before (virtual machines, MinGW), but this provides the best performance, with minimal technical headaches. That way, Windows developers need not be ignorant or locked out of the Linux ecosystem, and parallel to (2), those same previously Windows-only developers can more easily build for multiple operating systems.
(4) Windows works directly with LLVM to get Clang working on the Microsoft platform, in place of MSVC. The stated reason is, why force developers to use different compilers on different platforms, when they can just support ONE (Clang) for ALL?
By open sourcing their work, Microsoft has literally let go of a lot of their intellectual property; developers can and will fork this source code, and it will grow beyond Microsoft's control and reach. GitHub, meanwhile, is still based on Git; if Microsoft pulled any stunts with GitHub, nearly the entire user base is in a fair way to take their marbles and leave...to, say, GitLab, BitBucket, or any number of alternatives.
In short, while MS may be smoke screening, they are also cognoscente that one wrong move could put them in a bad position, wherein they have lost .NET, Azure, the cooperation of Linux, and the entire GitHub user base (which they just paid $6.5B for. They don't want to lose that!) They'd walk away from that with less than they started with.
Of course, remember that (5) Microsoft cannot just open source everything, without obliterating their profitability. I'm not going to ask for that. Frankly, I marvel at how much they HAVE open sourced.
In short, I'm cautiously optimistic. Microsoft has shown to be untrustworthy in the past, but let's see what they do in the present. As developers, we're all in a pretty powerful position to yank the rug out from under their feet if they turn on FOSS.
P.S. As a computer technician, I agree that Windows is garbage.
We agree on many things but particularly the low quality of Windows. So I trust your judgment. They paid $7.5 billions to be exact, but for business not for charity. You want to let them a chance, that's fair, but keep your two eyes wide open!
Oh, always! I never put all my eggs in one basket. I've got accounts on GitHub, GitLab, Bitbucket, and my own locally-hosted repository platform. And I've got local copies of everything. I never completely trust any online service, on the sheer basis that anything can happen.
MS definitely paid for business, but they (probably) aren't going to want to go and drive off their whole user base.
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