I'm sure parents back in the day thought the same about video games. You're lumping a lot of kids together there, maybe some of them will become journalists... Maybe social media is the only media that will even be relevant in 20 years when their career gets serious.
games could cause a lot of 'lost' time, but you had a say in games; there's a lot more consuming and almost no producing in social media use. And games did not cause you anxiety and FOMO, nor did they programatically lure you into spending your time and money on them.
99% of today's social media usage is the opposite of productive, too bad the laws concentrate on policing internet use though.