RSS was primarily a nerd feature in the first place, which is why it is so silly that Apple added it for consumers, not once, but TWICE. No one actually uses Safari RSS. If they did, why the need to then add it to Mail.app? Would it add even MORE value to add RSS to the Finder too? Why stop there, iTunes seems to have everything else in there already, one more tab that reads "RSS" wouldn't hurt.
Dashboard being a failure is clear. If it was a success (like the App Store), we'd still see Apple touting widgets and maybe even selling them. The fact of the matter is that there is no ecosystem of people writing widgets for this thing. Dashcode was largely repurposed as an iOS web app creation tool (also unused by all). So the result: no Kaleidoscope and hardly any Dashboard use.
Spotlight: It has been shown to be much slower than other tools (and was terribly buggy for many releases, where was the value back when it needed to re-index on every reboot and dragged your computer to a halt?) Most of the "Add on" features are broken too: if you type a simple formula into it, it will show the result, but you can't copy/paste it, so what's the point?
I'm not hating on Apple, they clearly get a lot of stuff right (such as Expose!), but their track record proves they get more stuff right when its their own idea. These little feature additions that seem designed solely to kill third party devs seem almost like half-hearted mini passion projects of single engineers that then die when they get reassigned to something else.
Feel free to directly address each of my points.