The author doesn't describe the most reliable indicator of new opportunity, which is economic change. Change can come in the form of shifting demographics, new tech, or new product adoption. These are the events that increase demand or decrease cost for a new product opportunity. They should be where you direct your attention.
> At any given time, there are dozens of industries operating within new and underserved markets that are experiencing rapid growth… This almost always represents a possible entrepreneurial opportunity.
His strategy might benefit from incorporating some of the things you mentioned — shifting demographics, new tech, etc.
Then again, one of the most common entrepreneurial mistakes is to develop a solution and go looking for a problem. That rarely works out, because most new tech doesn't have any business applications. It doesn't fit into the market.
So there's something to be said for a market-based approach, where you look for new things that people are actually paying for by examining high-growth industries, rather than simply looking at new tech.