I 100% believe in early intervention, not necessarily any particular kind.
1) because our kids aren't getting a natural raising (society backs off and does not understand enough for it to be natural)
2) The parents who have all done a ton of study like me ( or accidentally like mother in law) have all been succeeding because of steps that work that are equal to early intervention. Not all parents have the time (must work to get bills paid), energy or enough understanding of the importance to make it priority.
And with other children who are severe and not had early intervention we will never know their potential.
One thing that history screams out though is institutions which equal drugging, often abuse and definitely no intervention have caused the worst outcome.  And more recently trying the opposite of inclusion, assuming competency, intervention, love and patience has shown massive results.