If you join a quality gun forum, you'll get to speak to many of these middle men as well as many manufacturers on some forums with the first hand experience.
It's an interesting viewpoint. Much different than what's portrayed on the MSM.
In short, after the initial euphoria, they could not get any new inventory in. The new inventory was funneled to the tier 1 clients first. Typically, the very large business. The small business were hurt because of this. The local gun stores.