I would love to see the amount of resources that are used to produced each iPhone, because I don't have a big issue assuming that each phone brings, say 3 or 4 percent more utility to its user than the previous model would have.
So, assuming the battery is the most dirty part of the phone, I found the battery size for all the iphone models[0] and even if we exclude the the large ones, the iPhone 11 has a 54 percent larger battery.
The phones were released in 2007 and 2019, 12 years and 3 months apart[1]. That works out to a growth of approximately 3.3%.
So my original assumption was wrong, there has been an exponential growth in materials that nearly matches GDP growth.
[0]: https://itigic.com/how-much-battery-does-an-iphone-have-capa...
[1]: https://www.knowyourmobile.com/phones/every-single-iphone-re...
But you replace them every two years. And the market for them is still growing. And there's now a resurgence of a market for single-purpose appliances that happens on top of the smartphone market - not replacing it.
(It's also possible more matter goes into making a modern smartphone than a bunch of devices it replaced, because of the demand for more exotic and more pure materials in the processes along the way. But maybe it doesn't, maybe an individual smartphone is a net matter and energy saver. I can totally buy that, we've made a lot of efficiency improvements in manufacturing in the past decades. But there are limits to such improvements, and in the meantime, manufacturing as a whole keeps growing.)
Perhaps I've simplified my diagram too much - I should've drawn an additional "bypass" into "WASTE MATTER" from every other node, because every step in the pipeline loses some of its input as waste.