A couple years ago I bought an inexpensive Galaxy phone with service on a prepaid carrier. It was cheap, way cheaper than an iPhone would ever be new. It was a model that was supposed to be compatible with all 3 carriers the MVNO supported at the time.
Well, I unlocked it. And wasn't able to get it to work on ATT (whitelist), or a T-Mobile MVNO. I think the firmware was too customized to actually work on other MVNOs, even though it was unlocked.
iPhones, since Apple doesn't do special firmware for different carriers, don't have this problem. They may have some different hardware variants for different models, but they limit that too.
So an iPhone is likely to work everywhere nowadays, even if not optimally.
Well, I unlocked it. And wasn't able to get it to work on ATT (whitelist), or a T-Mobile MVNO. I think the firmware was too customized to actually work on other MVNOs, even though it was unlocked.
iPhones, since Apple doesn't do special firmware for different carriers, don't have this problem. They may have some different hardware variants for different models, but they limit that too.
So an iPhone is likely to work everywhere nowadays, even if not optimally.