I think the author's point of "made of dependencies, not files" is that they are not human files. They are autogenerated webs of dependent repositories, not to be touched by the user, unless something has gone seriously wrong. I wouldn't qualify personal files that are directly created and managed by a human user as being the same thing as a mass of folders curated and managed by a dependency manager utility.
I actually end up helping tons of random people in my company use conda, because they can't get the concept of virtual envs. They don't understand that the libraries are actually files on the disk, and your virtual environment is just a directory and some variables.
That's not to say all developers are like this, but I think the numbers that think like this are growing. Ultimately, I'm like you - they can pry the files from my cold dead hands, if I didn't know what/where/how files were used, I wouldn't fundamentally understand how a lot of different technologies even work.