2TB microsdxc cards have been available for a year or so, and 1TB cards have been available for several years and are even quite affordable. They work in many Android phones including my cheap Motorola. So it's Apple's sky-high premiums that has made their 1TB phones surprising.

https://www.bhphotovideo.com/c/product/1868375-REG/sandisk_s... 2TB $185

https://www.bhphotovideo.com/c/product/1692704-REG/sandisk_s... 1TB $90

https://www.bhphotovideo.com/c/product/1712751-REG/sandisk_s... 512GB $40