This is frequently asked question among webmasters; that xyz site has less content than mine, but it is on the first page of Google. Why should I add content to my pages?
SEO depends on several criteria. Google’s algorithms determine the positioning of web pages according to relevance of the proposed text content. Now nobody has a working knowledge of these algorithms.
You can add more pages / posts, you can also add more text content in a web page, but the quality is better than quantity. Your text content must be accompanied by other criteria for site optimization. Products or services your site offers must be explicitly described, organized and readable by search engine robots.