Complete guessing
But the mobile protocols are far more modern than landline protocols, so the concept of caller id probably didn't exist when they were first invented, but were easy to add to a brand new protocol like mobile ones

They then found a way to do it as part of the old protocols, but is not as easy, so you have to pay for it

Like I said, total guess though
( elusive I'm not really here. You're imagining me, Mon 11 Jul 2005, 15:26, archived)