A lot of the cheapness of these devices comes from the non-modulatity of them, basically the fact that the entire system is on one small chip (system-on-chip/So

A lot of the cheapness of these devices comes from the non-modulatity of them, basically the fact that the entire system is on one small chip (system-on-chip/SoC). You can't really have both this historic low-cost of items and expandability/modularity at the same time. Increasing the modularity means more interconnects, more complex case designs, etc, etc, which means much higher prices, not lower ones. You could argue that all of this comes at a mucher higher shared long-term cost in terms of more garbage, global warming, etc, and you'd be right, but good luck offering a highly expandable, "green" device alongside the latest SoC-device out of China (selling at 10% of the lowest cost you could possibly produce the former device for) at your local Walmart. People are simply wired to make decisions that benefit themselves in the short term.