The writing was on the wall last year that Google and other search engines were putting more and more emphasis on the mobile responsiveness of web sites. This is important for more informational sites such as our own Allegro site but it is critical for those companies that sell products directly over the web. If your rankings are reduced, your customers may likely find someone else to buy from instead of you.
As of this spring, Google changed their search algorithms to provide greater weight to responsive web design. Fortunately , they also then provided helpful tools to test your site such as their Mobile Friendly Test. Initially Google stated that this would only impact the ranking of mobile sites and not the more typical "desktop" sites but the true impact was quickly felt. Within the first week of implementation, pages on mobile sites were getting a huge spike in their presence on search engine results versus "desktop" sites using the same keywords.
The morale of the story is to make sure you pay attention to your Google tools and analytics. Make sure this new paradigm in search ranking doesn't leave you behind.