Google Ranking Factor – Thematic & Semantic Breadth
What is your site about? If your website is about a particular topic, then all of your content should reflect that.
Some websites may be about many different topics, and that’s OK too so long as some kind of topical hierarchy is built with related pages being physically interconnected more than between different topics, like via navigation and in-page links.
Google will probably rank a page independently of the topics discussed in other pages in the site, but other pages won’t likely gain any rank for topics not contained within the page.
It’s possible that if not managed carefully, Google may not be able to accurately assess what the core topic(s) is (are), and this may have a negative effect on the site as a whole.
Sub-sets of any topic should bear a strong relationship with their super-set. The site can probably gain good rank in many genres if each super-set is strong independently, and also has excellent sub-set content per super-set.
In other words, if your website needs to gain rank on several different topics, you’re gonna need a strategy solid content for exact topic, not one single strategy to cover all.