Intentionality and consciousness are demonstrably not the result of simple aggregation. You acknowledge this, I think, with the phrase "each device is in some ways more capable than one brain cell". That may be true, but the devices are not linked (and I would suggest, are not likely ever to be linked) in ways that would make them powerful the way neurons are.
They are not children. The do not develop. Individual instances are semantically prototypes which are destroyed or powered down, and the information gained from their existence is used by humans to create new ones. There is no "evolution" because there is no mechanism for variation beyond that which we, as humans, introduce. These machines are the perfect material for an intelligent design argument (one to which I do not subscribe). I do not see them as counterparts to, let alone examples of, biological evolution and development.
I do not subscribe to these attempts to find correspondences between whatever our current understanding of life/the brain/consciousness is and whatever current technology we have on hand. In the 1800s, people were doing this with hydraulics and gearing. Today, we're doing it with computers. It's so transparently parochial.
I don't doubt the theoretical potential for life as well as consciousness to exist on a non-biological substrate. I do very much doubt that the IoT is that substrate, and ditto for AlphaFoobar, GPT-N or whatever other computational marvel one might point to.