https://www.cnet.com/news/apple-iphone-xs-xs-max-preorders-kick-off-some-models-sell-out/

Preorders for Apple's newest phones began just after midnight Friday, and the larger and more expensive iPhone XS Max designed for Verizon and AT&T in the US appeared no longer available for delivery by launch day, Sept. 21. Many were now available within "1-2 weeks" or more, stretching preorder shipments into October, Apple's online store.

While Apple does leave some clues like shifting estimated shipping times for preorders, it's hard to tell how well devices actually sell, since preorder availability fluctuates based on how many devices the company can pre-produce ahead of their launch. About a half hour into preorders opening up Friday, many models appeared still available for for in-store pickup or shipped to customer's homes on launch day. In the past, some models of the phone sold out in less than 10 minutes.