Let's say McCarthy manages to win over the last holdouts. What's next? The concessions he has already made guarantees an utterly dysfunctional House. His Speakership would have a constant sword of Damocles over it. Just one member could impede him with a motion to vacate. There are at least 7 strong holdouts who would be more than happy to kneecap him.
The best McCarthy can hope for is a Pyrrhic victory, but it does not seem that he understands that.