Quite a few years down the road though. Yeah, DVDs will decline in use when DL'ing picks up, but not everyone is tech-savvy enough to do that.
The younger generations will be using the DL'ing more, but the older generations will still opt for the Discs. I consider myself very tech-savvy, but personally, i don't see DL'ing over-taking DVDs anytime soon - DL'ing will help to cover all the bases though, meaning, along with DVD rental.