> Safari outsources a lot to the operating system and as a result the interface and interaction becomes simpler, but less flexible.

Yes, definitely agree with that. But I think of "noise" as stuff that interrupts your normal interaction with web sites and in that regard I don't think Firefox is particularly noisy.

There are definitely a lot of features, settings and extensions with Firefox and while I don't use very many of them I do really appreciate the ones that I do use.

And much of the “noisiness” stems from tooltips, popups, etc explaining changes and additions. I can see where some users might want those but it should be possible to disable those entirely, or at least make them more “quiet” (e.g. a notification icon with red news count pip on the new tab screen where changes can be seen at the user's leisure).