If you have 10 problems to fix, the effort spent fixing the first 9 of them isn't "useless" as you say, just because you haven't fixed the 10th one yet. And the

If you have 10 problems to fix, the effort spent fixing the first 9 of them isn't "useless" as you say, just because you haven't fixed the 10th one yet. And they couldn't fix all of the issues by blindly proxying all IO through the main Firefox process, either, because that wouldn't fix the problem. It has to be able to _selectively_ proxy IO through the main process, and that takes time and effort to implement.