Children don't really watch TV (anecdotally). They watch YouTube, which is just as bad.
The key difference between television and video games of yore is the feedback loop. TV and video games were one shot deployed and then ratings were gathered after, averaging across the entire audience.
Now YT and video games don't have end states - same thing as social media. While you often won't have individual-centric recommendation algorithms in a video game, you have dark patterns and gambling mechanics in all the most popular games which is just as bad.
The argument really isn't that we need to ban children from social media, we need to guard their dopaminergic regulation the way we guard their physical and mental health... oh wait.
Ultimately its the responsibility of the parent (at least in the US). Parents who are aware of the pitfalls of high-dopamine-low-effort activities, poor diet, and low physical activity are going to guard against these things. The ones who don't will likely suffer later in life.