This is like arguing that front doors shouldn't have locks because burglary is illegal.
Legal status and practical enforcement are unrelated issues. You seem to be attempting to conflate them because you just don't like the idea of copyright.
But that's a different issue. In fact it's perfectly consistent to enforce copyright through a combination of DRM and legal challenges.
Legally copyright is the default. Nothing is in the public domain unless it's explicitly handed over to the public domain.
So software items with DRM can't be "stolen from the future public domain" because the DRM is part of the product or item. And it's up to the rights holder to decide whether or not they want to free it. This is a deliberate choice on their part. (It's a little more complex with other content because the content is assumed to have an existence independent of its realisation or distribution model. Not so much with software.)
None of this justifies Adobe's actions, and a class action against Adobe would also be reasonable. (Realistically not likely to succeed - but hardly baseless.)
But it would be an argument about real/assumed/implied breach of contract with buyers/license users, and not over copyright terms or DRM.
In 100 years from now, you will have software that is nominally in the public domain, but cannot legally be used, because all practically available copies will have DRM on it. The prohibitions of the DMCA's anticircumvention provisions do not merely prohibit you from breaking DRM on a copyrighted work. If that was the case, then this wouldn't be a problem: once the work falls into the public domain the DRM wrapping would have no legal force. However, the DMCA also prohibits making or distributing tools capable of breaking DRM. That means that as long as there's even a single copyrighted work protected by some DRM scheme, then you can't break DRM on otherwise uncopyrighted works.
This is sort of like living in a world where burgling old homes is perfectly legal, but lockpicks are also illegal, and so people who always locked their homes have basically opted out of the intent of the law.
I doubt anyone really believes that today's DRM will be any impediment to copying software 100 years from now. The problem is that DRM by its nature doesn't distinguish between uses that should be prevented by law anyway and legal uses that are only disrupted by the technology. If those anti-circumvention provisions you mentioned were abolished, that would be much less of a problem in practice.
That still leaves all the other questions about the duration of copyright protections, what fair use or the equivalent concepts should mean in an era of technological protections, and whether it's healthy for society to encourage perpetual rental models for creative work rather than permanent rights to access any given material, but these are separate (and potentially complicated) debates to be had.
It's more like saying that the police shouldn't protect your house if you didn't pay your property tax bill.
The only legal basis for copyright existing in the US is to provide incentives for creators to enrich the public domain. Any other basis is unconstitutional.
With DRM, creators are failing to live up to their end of the bargain.
Legal status and practical enforcement are unrelated issues. You seem to be attempting to conflate them because you just don't like the idea of copyright.
But that's a different issue. In fact it's perfectly consistent to enforce copyright through a combination of DRM and legal challenges.
Legally copyright is the default. Nothing is in the public domain unless it's explicitly handed over to the public domain.
So software items with DRM can't be "stolen from the future public domain" because the DRM is part of the product or item. And it's up to the rights holder to decide whether or not they want to free it. This is a deliberate choice on their part. (It's a little more complex with other content because the content is assumed to have an existence independent of its realisation or distribution model. Not so much with software.)
None of this justifies Adobe's actions, and a class action against Adobe would also be reasonable. (Realistically not likely to succeed - but hardly baseless.)
But it would be an argument about real/assumed/implied breach of contract with buyers/license users, and not over copyright terms or DRM.