...by apparently a professional economics journalist whose understanding of how capitalism works is staggering.
What would happen if corporations acted on his advice? You'd be pouring money into both the firearms industry and the firearms market. What does that mean? New entrants to the market, of course. Smaller companies like Daniel Defense already exist, serving a niche market within the niche market that is modern sporting rifles. Since you'd be flooding the market with cash and then removing the major competitors, you'd open the floor for a whole new generation of arms makers -- not publicly traded firms but, like Daniel Defense, small businesses owned by people devoted to excellence in firearms production.
They'd have money to spend on setting up shop, too, because you'd have enriched them by purchasing up their products. People who have been in the gun sales business could enter the gun production business with the billions of bucks you'd just dropped in their laps. They'd have every reason to do so, knowing that their customers were being starved of a popular item (and having the reasonable expectation that you 'good guy' tech firms were going to try to buy up all of their production line too).
This is the way to turn the gun industry from what the author calls "a financial pipsqueak" into a powerhouse. Gun tech startups would prosper wildly across the fruited plain.
It's a great idea. Go for it.