Actually the analogy is good. Having a physical token is very messy from a UX perspective. A menu is just as easy: If i want to use carrier A, i select carrier A in the menu, if i want to use carrier B, i select carrier B in the menu. This is what i do every day with my WiFi-network on my laptop....

Your µSD-comparison is what doesn't make sense. An SD-card can contain several gigabytes of data that would take hours to transfer to the phone. A SIM-card probably has a small key on maybe a few kilobytes that can be transfered and stored by any more or less modern communication-method, wired or not, within a few seconds.

But from a security perspective SIM is a much better solution because once you make the key transferable by software it will be much easier to steal an identity.

> Your nonalogy makes no sense whatsoever:

I'll agree it has several flaws. Still.

> Addresses don't significantly impact the phone's behavior (and its costs)

That would be a reason to keep the interface a physical token? Elaborate, please.

> phones don't need to reboot when changing SIM

The stupidly designed ones (with the sim behind the battery) does, but I see your point.

> people who criticize iPhones for not having a µSD slot

I was under the impression they miss the ease of data transfer and cheap storage space, not the act of changing the card to access other data. Please elaborate.