It started with my team at work getting together one day (almost a year and half back - some Trump BS was unfolding) and saying, if it gets too bad lets decide as a group to block ports/sites/apps etc on the company network. Slowly the list of things to block started growing.
It was really surprising how easily one could get consensus, that something specific was too distracting, effecting people and group productivity. Nobody wants to be the guy who says HN is addictive. But once someone says it at a meeting everyone starts nodding. News sites were the first to go. Then video. Then social media and most instant messaging/irc. We have moved to Signal to avoid some of the dark patterns in other IM/chat apps. And everyone is using the google/apple well being apps.
Almost everything is done on email or face to face these days. And almost 70 people now in what we call the noise cancellation club.
Right now things get unblocked during lunch time for 30 mins and after 5pm. There are common areas where things are unblocked, but they are intentionally pretty public spaces.
People of course can use their phones, but the fact that there is this environment available where it has become socially acceptable to be phone free, has definitely made a difference.