unarchive/extract/unpack/disassemble pdf

I know they have a very particular structure and such, but there are soft that have the ability to extract some parts of it. So is there something like an archive reader that can read through PDF like we can read through a Word file? I repeat myself, I know that’s not an archive, but I know it archive full-fledged picture files for example, and maybe the equivalent for text and such. I don’t search for a soft that extract certain type of data of it. But more like an archive reader that display all what it contains, so we can choose to extract and such, like any archive reader. A good deal of software that convert PDF into other files achieve extracting almost all information of it right and transpose it into another type of file, so why not an archive reader? It’s the same work without the conversion step, only reading one