While undesirable, this is less a bug and more a technical limitation. They did their best to figure out a way of getting all of the pieces of text into one single editor, separated by immutable markers between underlying binder items, but the programming kit just doesn’t have a way of doing that. Thus they’ve had to stick with the approach of stacking multiple discrete editors one after the other in a large scroll view. That is why Ctrl+A only selects one chunk at a time, why PgUp stops once it gets to the top of a section, why Ctrl+Home doesn’t scroll to the very top, etc.
Attempts were made to fake it, but this introduced fragility and too many bugs. So the decision was made to keep it the way it was in v1 and continue waiting for the right parts to arrive to make it work the way it is intended to. It was not an easy decision to make, and it was disappointing to have to make it, but some things aren’t feasible to do—particularly when a project is already running late in a public fashion.
As a staunch proponent of outline-based writing methods, and using Scrivener in that fashion: I do heartily agree with that, and it is unfortunate. We have some of the same friction on iOS as well, which also lacks the capability to stream multiple text files into one single editor instance—but even more so where there is no proper Scrivenings at all (just a read-only navigator, where you can scroll through seamlessly, and tap to jump to a section alone).
That all said…
But with the Windows Scrivenings defect, there is a downside, because there’s no way to view these text elements as part of the larger whole. (Yes, the feature exists, but it doesn’t work.)
That feels like a bit of an exaggeration to me. While I use Scrivener the way it is intended, and while there are occasions where these limitations get in my way, it doesn’t often reach into my awareness. So to say it doesn’t work feels a bit over the top.
I am sure there are factors that will make it more or less annoying for different people. I’ve never been much of a PgUp/Dn user given how it works on the Mac. On the Mac it simply manipulates the scroll bar without moving the cursor, making it purely a reference tool. Thus I have no habit built up for using these keys. The other thing I do a lot of is Ctrl+3 / Ctrl+1 style navigation, with the arrow keys being used to select the section I want to jump to, or when I want to move in a linear fashion, Shift+Alt+Up/DownArrow. To me, essentially collapsing the view to headlines and jumping to the spot I wish to navigate to is leagues more efficient than scrolling—whether by mouse or keyboard. Add on top of that being a Markdown writer that doesn’t generally need to format text, the boundary issue where you cannot format across section lines also doesn’t matter much to me.
To address the query of why it isn’t talked of more, some of what I described above could be involved, but there are probably more mouse users out there than you’re thinking of. So many people depend heavily upon the mouse for everything they do—and if that is how you interface with a text editor, then most of this stuff you’re talking about that makes Scrivenings “not work” simply don’t exist.