Yes, things are speeding up between the box office and the DVD. In some cases, the phim chiếu rạp are not even going to the box office. The same goes for releasing on the internet, as well as TV shows.
You're not the only one. I've noticed that phim chiếu rạp usually come out like 4 hoặc 5 months after it was released in the theaters, however it doesn't bother me that much if I never got to see the movie I want to see in the theaters.