Why does hentai anime usually suck?

Take a look at some hentai manga or doujinshi.  Regardless of the content, you'll see some amazing art work a lot of the time.
Watch a hentai video.  Terrible, repeditive animations.
WTF?

>>1
Guess they always dont have that much of an budget to support such animation everytime.
Look at strigendo by the way I think they only got around making one episode with really nice quality.
Also, Bible Black.