, and almost all windows machines come without them unless you're custom building it. Or if you stumble upon one of the last few prebuilt PCs that have that "tower" desktop structure - but many of those too don't have disc drives.
Dude. I sell PCs for a living. (I can't speak to Macs.) I repeat: in a retail environment, only about 30-40% of laptops do not come with optical drives, and pretty much ALL desktops still do (I'm sure there are some out there without drives, but all of the ones we sell have them). Desktops are by no means obsolete - there isn't as *much* demand for them, no, but they still sell regularly. And tablets are NOT outselling PCs of any kind yet - they are ramping up, yes, but they're still two different animals and there are a lot of things you can do on one that you can't do on the other. Only a small percentage of people are using them exclusively - the majority of them use them in *addition* to a regular PC. (there are also a shit-ton of people still using XP, never mind anything as modern as a tablet.)
Now, in five or ten years the pendulum very likely will swing to the extremes you describe, especially with hybrid/convertibles being so cheap now, but right now that's not the case.
I predominantly buy digital nowadays because it's just easier for me - I mostly only buy the disc when I want to put a little extra money in a band's pocket, or for collectible purposes.