Text is the Currency of the Internet
Relevancy is the measurement of the theoretical distance between two corresponding items with regards to relationship. Today, not only Google Inc. but also other search engines are quite good at calculating this measurement for text.
Google Inc. owns and operates well over a billion servers. The electricity to power these servers is likely one of Google’s larger operating expenses. This energy limitation has helped shape modern search engines by putting text analysis at the forefront of search. Quite simply, it takes less computing power and is much simpler programmatically to determine relevancy between a text query and a text document than it is between a text query and an image or video file. This is the reason why text results are so much more prominent in search results than videos and images.
Today, best SEO strategy is still emphasis on textual content than images, videos, and other formats. This strategy will likely have to change in the future as computers get more powerful and energy efficient, but for right now text should be every SEO’s primary focus.