I realize that I'm going to be a bit pedantic here, and it is not an argument I would support, but your statement *"Contrast with files, which I own ..." which is only true in a limited sense. If you have a book, in a file, which is stored on your device for your Kindle app, Amazon will tell you that you don't own it, what you "own" is a right to view it in the Kindle app for as long as your maintain your side of the agreement and Amazon doesn't feel like using one of their escape clauses.
Now I completely get how crazy that makes people, who argue "I paid money, I got this thing, I own it." but the only reason that it is in a "file" today is because Amazon hasn't figured out how to give you access to it without giving you a file. Nothing in the Adobe announcement changes anything, except that it provides for them, what they consider to be a better implementation of their rights management paradigm. Again, I don't condone or support it, but it's important to note that their thinking hasn't changed, only their implementation has. This also helps them to avoid you reverse engineering their files which they don't like because it allows you to circumvent their rights management tools. Again, I don't condone or support, just report.
So what may happen here is that something which has some value to a person, will be put outside their reach behind a price they are unwilling to pay. I understand that this situation sucks, but on the positive side it adds energy to the 'free' side of the equation because if there really is value there, it is only extractable if stealing is less easy than paying, and paying is at a market price that can support the energy of making it available. That price may be in programmer hours, not necessarily in dollars.