Wp themes are not the people will buy quality goods product types. Majority of premium themes do not code. Those items that have the critical mass are going to sell woth no sale price but new items will not get that high with “normal” prices. You had a lot of examples of new themes with 19$ prices and big sales. Or just check jupiter theme on popular list they were on cyber.momday sale and they got on 2 place. They got there price back up and got down again. Now they have again a sale and again second place. And again envato does not care fixed fee gives them more proffits overall prices fall, discount bring more sales and Envato earns more.