replying to myself:
one more way apple simply makes better software: safari offers a simple reset option that seems to reset all browser settings. Now, this doesn't help in the case of a user not understanding what went wrong, but I can tell someone over the phone "click on safari -> reset safari" far more easily than walking someone through deleting a firefox profile while saving bookmarks or reinstalling firefox and creating a new profile. I don't like safari as a browser, but it's to apple's credit that they offer this simple option so I tell my mother / mother-in-law to just click reset if the internet is weird.