I didn't mean just in terms of only image quality but also in terms of storage, and the overall experience of watching movies, dividing content into chapters, special features etc. DVDs were a pretty major jump from VHS. Blurays are basically just hi-def DVDs, which is great if you have a system where the difference in resolution matters but overall there's never been that much incentive.
For me also, I watch a lot of movies with my friends and with DVDs I never have to worry when bringing a movie to someone else's house or if I want to lend something to someone. Pretty much everyone has something that plays DVDs, either a dvd player or a computer etc. Bluray players are common enough now but its still a problem we run into. I have friends who will show up to other people's houses with a stack of unplayable blurays no matter how many times we remind them.