> > With SIM cards, users can switch to a new phone by just moving the SIM, or switch to a new provider while keeping their phone (assuming its unlocked) by just replacing the SIM.

> Unlocked phones are still relatively rare in the US so I don't agree with your second point either.

As you point out, where GSM networks are concerned, this observation is mostly specific to the US - swapping phones and swapping SIMs has been a reality in the rest of the world for years.

Instead, the main source of friction is frequency bands. When swapping phones, it's not often an issue when switching between locally distributed phone models, since they are the Asia/international models with more band compatibility. When swapping SIMs domestically, it's not an issue for the same reason. When swapping SIMs internationally, phone service typically works, but if you want high speed data _then_ you check for band compatibility.

I'd say that for most of the world, the reduction in friction is real. It's a pity that the US market is so different.