If your were in charge when the telephone network was designed, poor people would not even be able to make a phonecall to their middleclass neighbour or senator, they'd have to buy a special Rich People phone
Your hypothetical would make sense if iPhones didn't support regular phone calls, SMS, and every other messaging app out there. All people without iPhones can't do is send blue bubble messages to iPhone users. That's literally it.
On how messaging works on thousand-dollar phones? Yes.