They were going to do that back in 2011, but then cancelled the plans
I suspect there isn't a critical mass for a robust DVD service any longer. RedBox skims some demand for current blockbusters and a lot of people want content right now.
I really can't emphasize the right now enough. I'm never planning things I want to watch days in advance, so a by-mail service just doesn't work (plus there's the physical hassle of having to mail stuff all the time and dealing with the inevitable hassle of things going missing in the mail).
I just can't imagine waiting for something to come in the mail when I could instead fire up BitTorrent and be watching it 30 minutes later. The music industry learned their lesson from piracy but the movie industry still hasn't. Things will hopefully change now given that theaters are a much-reduced experience; they did always have the benefit over music in that whether you buy the music CD on launch day or pirate it digitally, the listening experience itself is identical, whereas seeing a film in theaters on launch day is definitely still quite different than watching some shitty pirated cam version, assuming the shitty cam version is even out by launch day (it isn't always).
I subscribe to both Netflix DVD and streaming.
I don’t much like serialized shows and maintain streaming mainly for my partner and the occasional one off.
Netflix’s DVD back catalog is thinning and I’m sort of at a crossroads about what to do.
I wish Netflix would spin off the DVD service and give it a chance to thrive.