No one is asking them to stop using libgit2 though. They’re going to continue using it. If they find a serious bug, they’ll fix it and continue using it.

The cost of all the additional hardware is just not worth it. If it was a choice between higher hardware costs, higher request latency, greater operational complexity of a new technology and rewriting libgit2 in a different language without all those tradeoffs, GitHub definitely chooses the latter.

But it’s never going to reach that point because they’ll continue using libgit2 compiled by clang forever.

That's very interesting to learn.