How pages buried in navigation hierarchy get buried in rankings too
Click depth measures how many clicks it takes to reach a page from the homepage through your internal navigation. A page 1 click deep (homepage -> category -> page) ranks significantly better than a page 3+ clicks deep. The effect is dramatic: pages 3 clicks from the homepage rank for half as many keywords on average as equivalent pages 2 clicks deep, and a quarter as many as pages 1 click deep. The correlation is real because depth signals to Google how important you think the page is. If your about page is 4 clicks from home, Google infers it's not critical to your site structure.
The problem compounds with crawl budget. Googlebot has a finite crawl budget per site (roughly proportional to site authority). It allocates that budget to discover and re-index pages. Pages closer to the homepage are crawled more frequently because they're reachable faster. Pages deep in the structure are crawled less often, indexed less frequently, and updated more slowly in Google's index. So a deep page not only looks unimportant to Google's ranking algorithm; it's also less frequently re-crawled and refreshed.
Flattening your information architecture to surface forgotten content
The solution is architectural flattening. Every page you want to rank should be reachable in 2 clicks or fewer. This means your navigation menu should expose top-level categories and subcategories. It means your footer should link to key pages, not just legal disclaimers. It means your homepage should have a featured section linking to high-priority content.
Secondary benefit is internal linking. Each page receives link authority that flows to its internal links. Pages high in the hierarchy accumulate more external link authority. When they link to deeper pages internally, they transfer some of that authority downstream. A page 3 clicks deep but internally linked 20+ times by high-authority pages can still rank well. The lesson is that depth is a handicap you can overcome with intentional internal linking strategy. But the easiest fix is to reduce depth in the first place. Restructure category hierarchies to be shallower and expose more content directly from high-authority pages.