There are embedded YouTube videos, MP3s, and code samples to illustrate what he's writing about. He's implemented their ideas using the Web Audio API and you can run the code from within the page and listen to the music being generated in real-time. It's a real testament to how great the web can be.
I think being able to do things like that is worth all the annoying parts of the modern web, in the end. For the developer and the end user. I wouldn't want to go back to the old way. I think it's easy to focus on the annoying parts and take the good parts for granted.
Doing something in a browser that we could do 30 years ago on a desktop isn't that great a testament.
Is this that much more efficient than "apt-get install foo"?
Not every platform/OS even has a (good) package manager. So I think this alone is what makes the web great.
Furthermore, free isn't free when my privacy is sold and/or my eye balls are subjected to even more ads. This is progress? No fucking way.
I don't know what you are on about as there weren't any app stores controlled by Apple or MS. Anyone was able to release crap software on floppy disks or BBS, and they did.