Found an interesting website on anime Blu-ray and DVD sale statistics. I was always under the impression that the majority of income was from Japanese DVD and Blu-ray sales but it seems there are more factors in play.
Anime merchandise is quite expensive. Especially when you import it and add shipping on top. And for those in Europe or in countries that charge duty on top I do feel for you. But it's good to know there are so many opportunities to support the studios out there.
Specifically though in regards to DVD and Blu-rays, the rankings through localised releases (FUNimation, Madman, Sentai, etc.) are not as prominent as buying the Japanese releases. But of course the majority of Japanese releases don't have English subtitles, so the only reason you'd buy Japanese releases is if you are either fluent in Japanese OR have a high passion for a certain anime series.
So basically source material (potential advertising) vs original titles influenced heavily by TV ratings. Sadly not much you can do here to influence this unless you live in Japan.
Feel free to check the website out, it's an interesting read.
Source: http://www.someanithing.com/sales-faqguide