^ Yeah, DVD quality is not great considering how cheap bluray is nowadays. Then again, if you have it, and you're watching on a smaller screen that doesn't need hig-res to look as good, it's still doable... and sometimes the DVDs still have the best extras that they've skimped on for later higher-res releases.
I honestly have gone to flea markets and picked up DVDs for a buck a piece for movies I wanted to see and might like, but wasn't sure I wanted to just leap in with a more expensive bluray purchase. or maybe it's a "junk" film that you wouldn't mind having but otherwise don't care much about. They're so cheap nowadays if you find the right outlet, as far as DVD goes.
---
you can use a variety of stuff still to watch DVDs and up, the issue mainly is that it's not as essential for LAPTOPS anymore because the marketing direction has been to use them essentially as portable terminals that stream data from a central hub, rather than being a "portable PC." Once you go slimline, you don't have room for the drive.
Case in point, my work laptop has the DVD drive, my personal laptop (HP Spectre) does not.. although it has wireless and cable hookup so I can just run in signals from something else.
Yeah, people have regularly used Playstations to run up through bluray, and I dunno if they can handle 4K yet. The home market is still decently strong because of 4K even if streaming has gotten more lucrative with the fast bandwidths available today. When you buy blurays or 4K, you'll typically get your streaming code too so you unlock the film on Movies Anywhere and you can stream to laptop. Basically laptops, along with smartphones and similar devices, are just items pulling data from the central hub now. But you will use standalone machines (I got a decent 4K player -- which does bluray and DVD and 3D as well -- and soundbar this past year) if you want high-quality viewing.