• one device = biggest phone
• two devices = 13/12 laptop or iPad Pro 12 + medium phone
• three devices = 13/12 laptop, iPad 10.5 + smallest phone
• four devices = three devices + watch / AR glasses
It does not take a genius to see that the iPhone SE form factor is the logical choice for Apple customers with three or four devices. These are the customers spending the most money in Apple's ecosystem.
In the absence of a product visionary at the helm, large companies may want to ask why US/EU customers purchased a product developed for the Indian market. Abandoning emerging markets' low-cost phones does not require abandoning the global market of customers buying a coordinated portfolio of fit-for-purpose devices.
On a secondary footnote, the creation of "Screen Time" is likely a pre-emptive defense against future lawsuits for smartphone health consequences, ranging from eye health to psychological effects on developing brains.
What reduces screen time? A small phone like the iPhone SE that can still be used with headphones for audio. So there is a legal argument to be made for small phones: the presence in a corporate product line allows liability to be shifted to customers — if you suffer negative consequences from screen time, you should have bought the small phone to discourage screen use.
On the other hand, if companies only offer large phones, and we find out years later that they knew the health risks of excess screen time were increased by large phones, they would have contributed to the problem instead of possible solutions (like the iPhone SE).