Australian fan here...

Over here, only up to Season 6 has been released locally. I was eager to get Season 5, so I had it imported, but I bought Season 6 locally and I figure I might as well wait for Season 7 and 8 to get released locally before I get them.

Anyway, I was thinking maybe the reason Seasons 9 - 11 haven't been released is because the rest of the seasons haven't been released internationally yet. Maybe once Seasons 7 and 8 are released in Australia, Paramount will focus on Seasons 9 - 11?

Just throwing it out there...