Not sure if they still do this, but Mozilla used to give new hires a little toy and say, "This is your million users; try not to abuse them too much." That concept is built-in to the culture there. Why take up space and memory for the 93% of users who don't use that feature, when an add-on can do just as good a job for the 7%?
It's just that companies like Facebook and Google are trying to lock in users on their own platforms.
Makes you wonder what is ahead for Blogger. It will probably be assimilated eventually.
Since only a minority of Chrome users are RSS users, it makes sense to have it as an extension. They're not stopping anyone from building one. So, hack away.
Firefox is basically at par with Chrome.
If your particular Firefox is slow, I suggest you reset your profile:
http://support.mozilla.org/en-US/kb/reset-firefox-easily-fix...