competition will still slowly raise the cap as technology improves.
Has not been my experience at all here in Sweden. Data caps have been lowered across the board over the past year as data speeds and availability has improved.
That's been my experience in the US as well. On EDGE/EVDO or even early days of 3G, unlimited plans were extremely common and fairly cheap. When 3G became more established and 4G/LTE started rolling out, 2GB is now the normal with massive increases in prices as you add more ($10/GB is common).