Very true, but the neuroplasticity observed is markedly different from forming entirely new pathways. It is more like changing the weights of a network already

Very true, but the neuroplasticity observed is markedly different from forming entirely new pathways. It is more like changing the weights of a network already in place. The neurogenesis is also limited to the hippocampus and olfactory bulb. Your cortex does not have a steady supply of new cells. Making these chips is really not all that expensive. Most groups produce only test chips in multi-project wafer runs, with a cost of 1-5k$ per chip. It is just like normal research, you have to make up experiments and then actually do them. So far there are a substantial number of successes in the domain of low-power neural networks.