Meat is expensive to produce. Insect protein is cheaper and more efficient, but insect farming technology is still very basic. http://www.openbugfarm.com
How does insect protein compare to plant protein with respect to cheapness and efficiency? What's the argument for inventing an industry when an industry already exists which provides plenty of healthy, cheap, and efficient protein for humans?
Insects are already eaten regularly by ~60% of the world's population. It's not so much inventing a new industry as improving the tooling of one of the oldest.
That said, there'll always be a demand for a variety of protein sources. We've had access to complete plant protein for thousands of years, but we consume more meat than ever. Vegetable protein will likely always be the cheapest, and that has been the case since the dawn of agriculture.