You can do all of that with SIM already. The only restriction placed is by cell providers. You either use roaming feature, or if you use SIM that supposed to us

You can do all of that with SIM already. The only restriction placed is by cell providers. You either use roaming feature, or if you use SIM that supposed to use multiple providers (like Google Fi) then it can use multiple networks. This change is bad for the customer no matter what. It's similar to me to what Verizon had during CDMA days.