I would argue that the change that happened was the realistic rise in price based on:

1) In 2017, the iPhone 8 was the 'standard', and the iPhone X was the 'premium above', adding new features for those willing to pay the extra 2) In 2018, the iPhone XS is effectively the standard, because the XR has the impression of being a hobbled version of the XS

Since noone would rather buy the 'hobbled' one, the base price jumps to $1000