Interestingly we visited a conference about mobile app development & site optimisation this week. There were a few of the industry leaders in mobile and some of the things they mentioned may be relevant:
The rise of “responsive” websites – while there are still those who for whatever reason do not feel the responsive boom (that’s a whole different thread!), to put it into context, there is a lot of interest in responsive designs on here and this interest is further damaging the mobile site market.
There are a selection of the “less experienced” design/developers on TF who through lack of experience perhaps feel daunted by the idea of the word “mobile” most likely considering it to be much more complicated in some way.
There is of course more “general” interest in creating standard PC based sites rather than mobile given the broader audience of users on mainstream platforms. From a UX point of view visitors to TF are more likely to browse and search refining by “site template” or “Wordpress” rather than mobile.
I guess there are a whole lot of reasons why you might not have featured the number of sales your theme may be due.
What I would question is why once the site was coded from your PSD it did not sell more – I would definitely be more questionable of a lack of sales from a working version.
Personally I quite like the design and hope it may pick up in the future.