b) is a recent(*) change. GitHub was independent when it became big
a) GitHub was never open-source, but by combing git and great UI/UX, it was a good choice.
Git is open-source and the distributed nature of git reduces the vendor-lock-in. You need to understand where we came from (svn or git to some ssh server). Coming from self-hosted git, embracing github did not take away your power over your own source code; you still had a copy of all branches on multiple machines. The world is different now, where github has become a single-point of failure.
(*) Update: Okay, maybe 2018 was not recently, but my point stands. GitHub existed long before the Microsoft purchase.
b) is a recent(*) change. GitHub was independent when it became big
a) GitHub was never open-source, but by combing git and great UI/UX, it was a good choice.
Git is open-source and the distributed nature of git reduces the vendor-lock-in. You need to understand where we came from (svn or git to some ssh server). Coming from self-hosted git, embracing github did not take away your power over your own source code; you still had a copy of all branches on multiple machines. The world is different now, where github has become a single-point of failure.
(*) Update: Okay, maybe 2018 was not recently, but my point stands. GitHub existed long before the Microsoft purchase.