What would be the point? If the goal is to "protect the children", then banning only 2 companies from providing social media to kids will do nothing after at most a few years - kids will just move on to the new social media that is not yet banned.

Of course, this says nothing about the many kids who will be hurt by being denied access to social media, such as the many gay or trans kids living in conservative families that found some solace in online communities that would accept the real selves they otherwise have to hide.