> removing the tech again is - at least to my knowledge - in experiment phase, too.

Do you not consider the period prior to the tech? It was a significant amount of time.

but so much has changed since

My hole point was that you cannot isolate it to phones. Phones probably are net negative, but even if you removed them: our society has changed and wherever the removal will be positive for their development is hard to isolate, hence it's purely based on opinion