Sure it has the simplistic file pickers and those are fine for a lot of people - but nothing close to the post I quoted, which limits it's usefulness for other people.
Sure, it's definitely close.
The quoted post talks about keeping files of different types in folders, that can be opened by different applications. In the "old days" of iOS this wasn't possible, but it's very possible today and easy to do.
"I need a home folder where I can create subfolders for each project." - Yes, you can create sub-folders in iCloud Drive using the iCloud drive app. I have many folders and sub-folders for projects, reference, material, etc. You can use other Document Providers like DropBox, Box, OneDrive, or keep files local using something like Documents, and they all have this feature.
"I want any app I work with to be able to open/save files from/to any folder." - Any app that supports iCloud Drive & Document Pickers can do this. Does every app in iOS support this? No, not yet, the developers need to support it. But the capability is there. Not every app on OS X actually uses File/Open/Save, the developers actually have to build that into their apps as well.
"I need an app which allows me to organize my files and folders. Something like Finder. Okay, maybe not as complex as the Finder, but at the very least I want to browse, view info, copy, move, rename, sort and ZIP files and folders." - yes, iCloud Drive app, the DropBox app, the Box app, the OneDrive app, the Documents app, etc. support this (with the exception of zipping files/folders).
Is the current solution perfect and on parity to OS X? Absolutely not, but I'd say it's finally at a 1.0 state. The Finder took 30 years to get to the point it's at, we've had this on iOS for only a couple years. It'll get better, but it's definitely a viable system to work with.