You're wrong. Though I don't expect you to change your perceptions.
There was an appeal for wide scale testing, before 4.0, giving
the reasons that the library redevelopment was quite good and stable now
and that they needed the applications to port, so they could finish
developing the new DE and get back to release discipline.
There was widely available info about the re-write, also the new Plasma
desktop, and everyone knew it wasn't finished.
The clear implication was that there'd been insufficient testing
The problem for a project like KDE, is it's hard to download the source,
just spend a few minutes doing ./configure; make; make install. They
needed a release infrastructure to make it feasible for most to try it out,
and submit bug reports. In practice that requires support by the distro's.
What KDE were, was naive about the process. Now I'm sure they see that
the approach to migration taken by developers of ext2/ext3/ext4 has a lot
to be said for it, to avoid PR problems. Especially as Desktops are an
area that hotheads find much more interesting than boring filesystems.