You are dragging anti-corporate ideology into a very simple matter.
Corporations are sometimes users, and individual people often benefit from denying access to the source code of software that is used to provide a service.
Providing a service is fundamentally different from providing software.
There's nothing anti-corporate about it. The AGPL is motivated by the same thing that motivated the original GPL: making sure that users have access to fix bugs in the software they're using, like in the printer driver anecdote.
The AGPL doesn't require you to provide the source for software that you're using to provide a service - only the source for software where the software is the service. A bug in software I use is equally annoying when I'm using that software over a network connection as it is when I'm using it on my local machine.
That's a very simplistic and, I think inaccurate view of the matter.
My customers, for example, to whom I provide service, are not infringed upon in any way because I use private forks of GPL software in the provision of my services.
> My customers, for example, to whom I provide service, are not infringed upon in any way
The issue is that I—and, more importantly, your customers—must simply take your word for it, since we're unable to confirm or deny it for ourselves if you don't make the source available.
When dealing with large corporations, taking such statements at face value is pretty foolish.
This is an interesting point. The original question was what if my database was AGPL, and it's source code was modified. If this database was used as part of a public (cloud-based) web-app, how could end users ever know there is a custom database? You are right: It seems likely that less ethical orgs would just lie and say they use the database unmodified. Thus avoiding the obligation to publish their database modifications as required by AGPL.
They will be when you go out of business and disappear, and they can't compile that same service to run on their own replacement server because you've withheld the source to your modification.
You might not want to admit to yourself that your business model is based on infringing on the freedoms of these users of GPL software, but that's exactly what it is.
Corporations are sometimes users, and individual people often benefit from denying access to the source code of software that is used to provide a service.
Providing a service is fundamentally different from providing software.