Many people still like owning a physical disk. For a movie lover, if you like this movie, you want to have it, collect it, and whenever you want to watch it, you can watch it with just one player. This is why I will always use dvd.
Still, more important than the tangible part of owning a movie is actually watching the movie. I do stream online sometimes, but I absolutely hate the buffering which you never experience on optical disc. Plus, I never feel like I own it like I would feel with owning the Blu-ray or DVD. That can be a good thing at times, because there are some movies you don’t want to own, but you just want to watch. Plus, I prefer watching my movies on TV over my laptop. As for Netflix, it is far more convenient to buy a disc, put it in a player, and watch, than paying bills to Netflix.
By this point, many people also had MULTIPLE DVD players in the home. Most people would be reluctant to replace all these. Even if you brought one Blu-ray player for the living room, when purchasing a new film, would you buy one which you can view on ONE of your pieces of tech, or ALL of them?
Meanwhile, LEGAL streaming services actually have quite a limited number of titles available. New releases are often delayed compared to the physical media releases. Combine this with the above points, and you're left with quite a number of people who will be purchasing these films on DVD.
This article may bring too much personal subjective awareness, people can continue to use dvd for a variety of reasons, such as Internet access may be spotty/unavailable for streaming on demand and physical copy means one doesn't have to download or store data. But it is undeniable that DVD can fill the gaps that technology brings to us. People often forget their intentions because of the progress of the times.