I think there is some herd mentality on design trends, but overall with UI patterns it's actually useful to follow certain standardized patterns so you don't ha

I think there is some herd mentality on design trends, but overall with UI patterns it's actually useful to follow certain standardized patterns so you don't have to train the user that much. All of the things you described are not really any good UI or design patterns, but probably something from a "growth hacker", that were a/b tested and increased engagement metrics, so they got added. They didn't get added because someone saw them somewhere else, or the designer really wanted to add social media sharing buttons, 3rd party toolbars or interrupting the user with useless stuff.