I felt like my family was lucky to get through 7 DVDs a month with one-at-a-time. We had a pretty good 3-4 day turnaround, but no matter how hard you tried to watch every movie the day you received it, we always managed to end up holding onto a disc for a few days. We eventually switched to 2-at-a-time so we could have one in-flight and one at home, that helped smooth out the gaps.
But even counting 2 or 3 at a time subscriptions, with unlimited streaming I am able to consume more content in a week and a half then I could in an entire month with DVDs, so in terms of content viewed per dollar I still think I'm getting a good deal. Streaming is especially a boon to anyone binging on a TV show. DVDs would have 3, maybe 4 episodes per DVD, so going through a show could monopolize your subscription for weeks at a time. Today I pop the show I want on and it just goes and goes.
Another big change is BluRay, which I've found has far and away higher quality than streaming of any type.
Standard Blu-ray (As opposed to UHD Blu-ray) doesn't have, to me, subjectively better (or even as good) quality than either 4K and/or HDR content available from YouTube, with the particular data connection I have at home, and with the screen I use. (I'm not currently paying for the 4K service from Netflix.)
I haven't actually compared UHD BluRay to 4K/HDR streaming. But a lot of this is going to vary by streaming provider, codec, data connection, and display hardware.
Absolutely. Blu-Ray usually have ~18-25GB of raw video for a standard 2 hour 1080p film.
It's usually actually more because of the container format but the actual video itself is usually about that size.