That's a problem because "using a screen as a babysitter" likely correlates with overworked poorer parents and thus a whole host of other developmental problems
And banning screens for the first several decades of your child's life correlates with being a billionaire.
Even for upper middle class parents, "using a screen as a babysitter" just means you're more stressed and have less hands around. My kiddo has not seen a screen at the age of 2, but that's just because he has two parents at home at 5pm everyday.