Its going to be a very long slow death for DVDs. Nothing like it was with VHS. Blu-rays and dvd are the same format and can be played in a Blu-ray player. You can't exactly pop in a VHS tape into a dvd player... well you could try but not sure what that would accomplish. They actually still have VHS tapes for rent at my local library. I think dvds/blu-rays will still be around by the time I'm dead and buried. Someday Hollywood is going to embrace legal electronic ownership of films like the music industry does with music but right now on demand renting or disc purchasing seems the way to go for the time being.
Eventually I want to put all my dvds on a portable hard drive. I don't care much for extra features so they'll just be the main features. I'd pretty much need a 10+ TB hard drive to store all my movies so I wanna wait a bit for those to come down in price. I have so many dvds and they take up so much room on my shelves.