I believe the distinction that separated the US from the rest of the world is that US carriers charged the recipient of a message, while the rest of the world charged the sender. I don't know if that's true for evrryer carrier or if it's still true today, but it made a major difference.
It's also the reason apps threaten you with fees ("this service may cost you money") when all they do is send a verification SMS. Receiving messages is free in most places but because of a handful of shitty carriers apps now have this warning embedded in them.
It’s actually a “shared cost” model, not really “called party pays”, as far as I know.
And as far as I understand, this is all downstream of US mobile numbers not having a dedicated prefix identifying them.
They have region-specific area codes just like landlines to which calls are physically routed, and from there it’s routed onwards to wherever the mobile phone might be. That could well be a long-distance leg of which the caller is unaware, so it would be surprising to bill them for it. That leaves only the called party.
This model was then probably just carried over to SMS.
US carriers haven’t charged for long distance calls for decades at least for domestic calls.
Besides with number portability, you can keep your same mobile number when you change carriers no matter what the original region was. I’ve had my same number for over 20 years and have changed carriers 5 times.
They're largely not charging end users for it anymore because the cost is just too low these days, true, but as I understand that's still how the pricing model evolved.
> you can keep your same mobile number when you change carriers no matter what the original region was
Yes, but only because all carriers have physical or at least logical/rented infrastructure in effectively all "rate centers" [1]. The call still goes to whatever rate center your number corresponds to (barring other agreements, I assume, e.g. the originating and terminating carrier having VoIP interconnectivity).
That's very different in countries that have dedicated prefixes for mobile numbers: The originating carrier can immediately detect the target network (instead of target region) from the prefix and route the call to the nearest interconnection point between the two.
This means that the terminating carrier usually carries the traffic for the longest geographic stretch, something for which they usually/historically got to bill the originating carrier via interconnection fees. Today, these fees are either gone or nominal/heavily regulated, but the more efficient routing is still a factor for reliability.
Explicit charges are very rare these days, but there are at least still metered plans that count both incoming and outgoing texts against a monthly maximum.
It's also the reason apps threaten you with fees ("this service may cost you money") when all they do is send a verification SMS. Receiving messages is free in most places but because of a handful of shitty carriers apps now have this warning embedded in them.