at least in the US, most people are fine with iMessage/SMS since

* pretty early on the vast majority of phone plans started bundling unlimited text messaging, which IIRC was a big motivator for using messaging apps abroad

* because of the vast scale of the country, domestic coverage results in no roaming for the places Americans spend most of their time, unlike in Europe where there are multitudes of countries you'd be passing in a one to two hour flight. Roaming charges in the EU were only abolished in 2022, late enough that everybody has settled on apps as the best way to manage that now.

* many American plans extend unlimited messaging to Canada and Mexico, the two likeliest places that Americans would go to abroad