So if I had to write a tl;dr I would say that there are two economic incentives for neuromorphic computing:

1. Energy efficiency: More brain-like computers will eventually an energy efficiency comparable to the human brain. Consider that AlphaGo Zero used ~200 KiloWatts for learning Go vs. a human that uses about ~20 Watts for learning everything that humans can learn.

2. AI & Neuroscience research: What better way to test neuroscience theory than to physically build a brain? As the saying goes, if you can't build you don't understand it.