Assuming that's true*, it honestly isn't good reason to give your kids a smartphone. Your job description as a parent is pretty much to stop your kids from doing things they don't understand will hurt them. There's (imo) plenty of evidence that smartphones are hurting kids, and therefore it's a parent's job to crack down on it even if it costs them in their social life. Like, if all the other kids were shooting up heroin it would be considered insane to say "you have to let them do it because all their friends are junkies", and I don't see it as being different for phones.
*It's also not clear that your premise is even true. Plenty of parents in the past have reported how their kids' friends adjusted just fine to not being able to use a smartphone to contact them, and that they still had healthy social lives.
> There's (imo) plenty of evidence that smartphones are hurting kids, and therefore it's a parent's job to crack down on it even if it costs them in their social life.
From personal experience, being isolated as a kid can also be profoundly psychologically damaging and stunt development of normal life skills. Sure, see if the kid can get by without a smartphone for as long as possible, but if they do wind up completely excluded it's time to reevaluate the cost-benefit analysis and potential ways to mitigate smartphone overuse, not just think that the isolation is "okay" cause you're protecting them from phones.
And everything I've ever delved deep into how the studies were conducted, what were the real conclusions drawn, the type of content being shown, etc. never leads to what the news would have you conclude. It's basically a terrible game of telephone where parents just end up getting fear mongered into limiting device time to 2 hours a day because someone said so. Utter nonsense.
There's a lot of people making claims based on paid research with agendas to sell fear. If you think you have some real empirical evidence that will standup to scrutiny, by all means share.
*It's also not clear that your premise is even true. Plenty of parents in the past have reported how their kids' friends adjusted just fine to not being able to use a smartphone to contact them, and that they still had healthy social lives.