A recent report from Gene Munster’s Loup Ventures (via 9to5Mac) has noted that the iPhone X could already be hurting the iPhone 8’s sales despite the fact that it has yet to be released. This is based on the estimated shipping times for the iPhone 8 and 8 Plus, which despite going live last week appears to be remaining the same the following week at an estimated 1-2 weeks shipping time.
Based on previous iPhone releases, the longer one waits to pre-order an iPhone, the longer the shipping times will slip due to overwhelming demand. For the shipping times to remain the same suggests that maybe demand for the new iPhones might not be as big as Apple had anticipated, and that many could instead be holding out for the iPhone X.
Alternatively it could simply mean that Apple has gotten a better handle on inventory and are producing more units than before to meet the demand for the new iPhones. We will have to wait for the official numbers to be released to see if there really is a correlation between the releases. In the meantime analysts are predicting that the iPhone X could be severely constrained well into the first half of 2018.