The one thing that annoys me to no end - and that I feel should be somehow legislated into oblivion - is paying for a product but only then getting access to said product for as long as the company behind said product decides to allow or support it, after which access is removed or blocked.
If I pay to buy something (as opposed, say, to rent it) I naturally expect to own that thing for as long as I want to own it*. Never an issue with a physical thing I can touch such as a book or a shirt or a bicycle, but seemingly more and more often an issue with digital content that has no physical form.
* - thievery and suchlike notwithstanding, of course...
You probably don't read Software License Agreements / End User License Agreements do you? Or other legal docs that go along with digital content?
I don't disagree with you, mind. But I understand that when you purchase something, you may not purchase everything and complete unrestricted access to something. You "buy" a house or a piece of land, you usually don't get the water or mining rights for that piece of property. You "buy" a product at the store does not give you the right to reveres engineer and produce copies of it. You "buy" a book means you have the physical copy, but it doesn't mean you can reproduce or redistribute it. You "buy" a digital product your rights are limited too.
If it's important to you, then you should read the legal terms of what you are buying.
For instance, Roll20 has this (to me) very important part of it's
Marketplace EULA;
2.1 You agree that Roll20 may stop (permanently or temporarily) providing the Marketplace (or any features within the Marketplace) to you or to users generally at Roll20’s sole discretion, without prior notice to you.
See also section 3.9 and 7.3 (c) for additional clauses that allow your "purchases" to be removed from your use/access.
And from the
Terms of Service;
Orr Group reserves the right to revoke the authorization to view, download and print the Orr Group materials available via Roll20 at any time, and any such use shall be discontinued immediately upon notice from Orr Group.
All of which is completely reasonable, and probably necessary for a SaaS product. It would be crazy to guarantee perpetual access to something you "buy" from Roll20.
Of course, that's for a SaaS product. Fantasy Grounds has no such reasonable restrictions because as a client-server product they don't need it. Read there
EULA.
To me the difference between these two architectures and their licensing was important to me. It was one of the top reasons I chose FG over Roll20. But it might be why you chose a printed book over one of the various digital formats.