I have doubt on the price. As I know, in some Chinese high-end restaurants they sell dog meat for about $8 a pound. On local markets it might be less than $2 for a pound of processed dog meat, while the lean beef is over $3 a pound. I don't think dog meat is more expensive than beef in China or Korea.
if you know a little about Chinese culture or Korean culture which is deeply influenced by Chinese, you may know a proverb that says "dog meat can never be put on a table", which means dog meat is not a decent dish to serve guests.
Not sure about beef, but pork and chicken, both of which are plentiful, are cheaper than dog meat. As far as that $800 figure, the article wasn't clear if that was in relation to dogs shipped to Korea from the US for breeding purposes, but I'd think that's what they meant.