They didn't just maintain it, they did years of work on it. And again, it was not because it was C. Its because it was literally millions of lines of C from 80s

They didn't just maintain it, they did years of work on it. And again, it was not because it was C. Its because it was literally millions of lines of C from 80s and early 90s and with a sub-optimal architecture. And there is likely a reason the original people didn't continue to work on it.