I agree that using exception is hardly noteworthy these days, but consider that in the context of a codebase that has evolved for more than a decade. I guess, ten years ago, "let's not use exceptions; they aren't worth it" was more justifiable.

In any case, the decision was made, and we have millions of LOC where every single API is built with the assumption "No exceptions here." In that context, introducing exceptions seems suddenly a lot more trouble than its worth. Well, YMMV, and in any case I'm not a decision maker so what do I know.

* BTW, I think "a single codebase maintained by thousands of engineers" is the single best thing I found in Google, as it opens up infinite possibility of learning new tricks, new APIs, and sometimes new projects. (Of course, everybody complains that every API is implemented at least three times, but imagine how worse it would have been if every project had its own codebase.)