What you personally think is a fair price, and reality, don't necessarily align. Apple has always tried to maintain a certain profit margin percentage since the beginning of the iPhone (as should any successful corporation). Matter of fact, based on the numbers in this article, the profit margin % has actually been higher with older phones that were priced cheaper as it cost much less for the bill of materials.
The newer phones cost more to make and Apple is choosing not to sacrifice profit margin in doing so. Even compared to new Samsung phones, Apple's profit margin is only around 5-7% higher. The profit margins do not take into account the costs of marketing, research & development, logistics, staff, packaging, software, etc.
Today's phones do last as long as you wish they would. And while I am sure everyone would like a less expensive phone....no one forces you to pay the prices. There are alternative devices, the ability to hold onto existing phones longer, etc. If you want new tech with advanced features, it will come at a cost.
https://www.techwalls.com/production-costs-of-smartphones/