Yesterday I was ready to jump-ship to GitLab, but after thinking about it more and reading about it more, Microsoft acquiring GitHub isn't all that terrible, or surprising.
It's been known for a while that GitHub was basically bleeding money, and was likely well on their way to running out of the 250 million that investors gave them. When GitHub runs out, either their investors give them more money, they're forced to go out of business, or they look to be bought out by someone. If the investors don't think GitHub has a path to profitability (which they don't as of now, they simply don't make enough from enterprise customers) they're unlikely to invest more money into GitHub, leaving really only 2 and 3 as viable options. 2 obviously would be catastrophic, which makes 3 the best available options.
Out of all the possible people to buy GitHub, Microsoft is actually probably the best. The other tech companies that have the money included Google, Amazon, Facebook, Oracle, IBM, Apple and maybe a few others (RedHat? As happy as I'd be I doubt they have the money). Facebook is bad for the obvious privacy concerns, Oracle has a history of big "fuck yous" to the open source community and would probably be the worst of the ones I named, IBM is... IBM? They haven't done much with the open source community and don't seem inclined to. Amazon has been actively hostile to open source in the past. Which leaves Google, Microsoft, and Apple.
Apple's a bit of a mixed bag in the open source world. They do some things very publicly, namely webkit, and have recently open-sourced their kernel, but overall they're not known for being the friendliest face in open source software. Google has done quite a bit in open source, but there are similar privacy issues with Google as there are with Facebook, and Google is arguably a larger corporation than Microsoft.
Microsoft on the other hand has been embracing open source, largely out of necessity to maintain their top talent. Between VS Code, dotnet, Chakra, TypeScript, and even dumb things like Powershell, Microsoft has arguably been one of the most active companies in open source. In addition, Microsoft is one of the best companies to make GitHub profitable again without major changes to the end user experience. They can cut costs in huge ways, thanks to being able to migrate GitHub from AWS to Azure, and being able to integrate a lot of GitHub's HR and management teams into their own.
In addition to cutting costs, Microsoft can likely increase the revenue of GitHub without changing anything about the service. Microsoft has very well established enterprise sales routes which could lead to an increased adoption of GitHub Enterprise, thus raising GitHub's profits and getting them out of the ditch they're currently in.
MS acquiring GitHub is the best possible outcome for what GitHub's current situation is, and could actually lead to improvements in GitHub thanks to the more sustainable profits.