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Nothing Phone builds a blue bubble iMessage bridge while Google and Apple fight over RCS
(www.androidcentral.com)
This is a most excellent place for technology news and articles.
There are always four decisions at play - country of origin of sender and receiver, current location of sender and receiver.
Whenever you enter a different country, you gen an automated SMS informing you of the prices of SMS, MMS, outgoing and incoming price calls per minute.
Rule of thumb used to be - SMS receiving is always free, accepting a call with local SIM card is also free. All the other combinations are usually extra if you are currently in a different country than the SIM origin.
But, now that most of EU is either in Shengen or is a partial member with contracts (like Croatia with mobile internet), you either don't pay as much or pay no extra at all.
But, yeah, that's probably the reason SMS never really got off.