Owning media and owning the copyright to the media aren’t the same thing. There is a well recognized right to resell and transfer physical media, regardless of what the EULA says. You can’t sell more copies, but you absolutely sell (or gift, or leave in a will) the copy you have. The question here isn’t whether you should have a copyright on your digital purchases, it’s whether your rights to digital purchases should be analogous to your physical purchases.
Owning media and owning the copyright to the media aren’t the same thing. There is a well recognized right to resell and transfer physical media, regardless of what the EULA says. You can’t sell more copies, but you absolutely sell (or gift, or leave in a will) the copy you have. The question here isn’t whether you should have a copyright on your digital purchases, it’s whether your rights to digital purchases should be analogous to your physical purchases.