Numbers do not lie. So, assuming the compilation is accurate, accounted for, and covers all the product SKU, I'll agree that it performs better than Road to Ninja (though somehow I only see RTN Limited Edition only in the list, but I digress...).
If anything, it just says that these are the trends of anime storytelling nowadays. Quality of the story is no longer becoming a priority. You can have a poor storyline, bad morale message, etc, but as long as you put in Moe character with big breast, you'll get monetary success.
Yikes, ... and I thought lolicon, ecchi and 50-shades are bad enough... ;)
Look at the link. 18,000 was the number of sales that RTN made in the first week, not the whole year.