James, you give a great template for how a business needs to move forward in their chosen niche online. Quite informative and the meeting of minds has been something a number of us have done online and in person to gain better insight into our small similar businesses. Thank you for sharing your detailed approach to increasing organic traffic...content still is king.
If both page are closely related (lots of topical overlap), I would merge the unique content from the lower ranking article into the top ranking one, then 301 redirect the lower performing article into the top ranking one. This will make the canonical version more relevant, and give it an immediate authority boost. I would also fetch it right away, do some link building, and possibly a little paid promotion to seed some engagement. Update the time stamp.
Having large groups of content that all revolve around the same topic will build more relevance around keywords that you're trying to rank for within these topics, and it makes it much easier for Google to associate your content with specific topics. Not only that, but it makes it much easier to interlink between your content, pushing more internal links through your website.
At our agency, we work with sites of varying sizes, from very large to quite small, and recently, we have noticed a trend at the enterprise level. These sites aren’t relying as much on Google for traffic any more. Not only are they not relying on Google traffic, but also, the sites are getting less than 10 percent (or slightly more) of their organic traffic from the search giant.