Apple did introduce 'flagship' models with the iPhone X, but the same year they also had the iPhone 8 which was on the same trend line as the iPhones 4S to 7.
And to speak of the "iPhone 13" is kind of vague: you have the 13 mini 128GB at US$ 700, and the 13 Pro Max 1TB at $1600. On introduction, the 3G 16GB was $700 and the 4S 64GB was $850:
Also worth remembering that depending on how you value inflation, $700 in 2008 when the iPhone 3G launched is somewhat over $800 now.
A more interesting question to me would be how the average buyer's cellular plan has shifted over that time — people tend to focus on the phone prices but not the greater monthly service charges.
Countered with the deflation of getting more capabilities for the dollar. Even a current lower-tier iPhone is much more capable than many flagships from a few years ago—never mind things that weren't even dreamt of, like 1TB of storage.
iPhone prices have been fairly steady for the "regular" models:
* https://www.gsmarena.com/price_history_of_apples_iphones-new...
Apple did introduce 'flagship' models with the iPhone X, but the same year they also had the iPhone 8 which was on the same trend line as the iPhones 4S to 7.
And to speak of the "iPhone 13" is kind of vague: you have the 13 mini 128GB at US$ 700, and the 13 Pro Max 1TB at $1600. On introduction, the 3G 16GB was $700 and the 4S 64GB was $850:
* http://www.asymco.com/2021/09/21/the-most-important-iphone-e...