With the virtual SIM, shouldn't the customer own the SIM? Apple should allow me to download a virtual SIM from a carrier, then put it iCloud. Now I can store all of my SIMs securely, maybe even switch between them on my phone. They could be encrypted somehow, so even if someone stole my iPhone or hacked iCloud the encryption password or keys wouldn't be on the phone. You only need the keys or password when swapping SIMs.
I don't think that Apple wants to be involved at all when you swap Virtual SIMs, there is nothing in it for them. The convenience of tying my Apple ID to all of my SIMs means nothing to physically lose. And maybe there will be a way to have both a Virtual SIM and a physical SIM so you can put it in phones that don't have the Virtual capability.
And maybe Apple will bridge the gap, allowing the iPhone to turn a physical SIM into a virtual on the phone and vice versa as a intermediate step as manufacturers move to virtual. That would be pretty cool.