OP posited: “Apple's been taking a number of steps over the last few months to show that they take Safari/WebKit development seriously. This is another positive step in the right direction.”
You basically responded, “They're still not as good as I want them to be!” It's a point that has nothing to do with the original comment, which was about improvement, not perfection, and about how seriously they take Safari/Webkit development, not about their release process (which remains roughly the same as it has been for the past many years).
Additionally, regarding the workarounds you mention: they are unnecessary in a “normal environment with rapid updates” only when those developers decide to fix your bug. Again: rapid updates are only useful if your bug is being addressed. I've got workarounds in my code for issues in Firefox that probably won't be fixed anytime soon, and features that Firefox and Chrome support poorly that they won't support well for a while, etc, etc.
I'm not saying Apple couldn't be releasing bug fixes for Safari on any platform faster—they certainly could. But you made an unrelated complaint as a reply to a specific comment, and your argument seems suspect to boot.