ODEX probably gets a bulk licensing agreement from US companies.
Licensing anime ranges from the hundred thousand mark to the millions. And it depends on a lot of things. Popularity, demographics, sub-licensing, etc. US companies try to go for profitable series. If a series is not deemed profitable, then most companies will avoid it like a plague. Let's pick on "Kodoma no Omocha". For the longest time, that series was not licensed. It was popular, so that means that Japanese companies have an advantage in requesting how much they want for the license. The series ran for 102 episodes. That's production costs there. At 4-5 episodes/DVD that's still 20+ DVDs to produce for the series domestically. That really cuts into costs. But eventually, it got released but only after years of waiting, almost 10 years.