Let me express some skepticism here: from own Abantecart website experience, this didn't happen, and the mobile search share is still just a drop in a bucket of desktop searches... Of course, the size of this drop depends on your website (or product) specifics, but independent sources like for example research by the Nielsen Norman Group suggest users still very much prefer Desktop/laptop for making most e-commerce transactions, and it may take a long while before the mobiles will overtake it..
Surely, this is great to have your website usable both for mobile and desktop; the question is, are there enough developer resources to develop both desktop and the mobile versions at the highest quality level in the free Abantecart? The adaptive type (automatic resizing of images and layout while keeping overall style) of mobile design that is already embedded in the shopping cart's code, is not perfect (it has limitations) but is a low-cost compromise (compared to deploying and running additional, fully mobile website). Is the mentioned non-free mobile template much different (or better) than the original adaptive code?