Name brand cases have been $50 to $80 each for at least a decade. I assume many people simply buy cases sold by Chinese companies that do not design their own cases. Such cases that have built-in MagSafe-compatibile magnets are available on Amazon and AliExpress for under $20 each (e.g., $15.19 YMHML Magnetic, $19.99 Sinyoeer Carbon Fiber).

Also, inflation plays at least a small role. When the first iPhone was released in 2007, it retailed with a starting price of $499 with a two-year contract; $499 in June 2007 is $711 in December 2022 when adjusted for inflation. A decade ago, the unlocked iPhone 5 retailed with a starting price of $649; $649 in November 2012 is $837 in December 2022 when adjusted for inflation.