I don't think that we are really disagreeing on the goals (although since I am using a KDE desktop right now, I disagree with the statement that it's "unusable" :-)
People want their systems to work. if an upgrade breaks things, it's a problem
However, Mark is correct when he says that one of the lessons that people keep re-learning is that if you have a hard thing to do (in this case, shipping a solid release), focusing on the problem and figuring out how to make it more reliable and easier to do so that you can do it more frequently results in many unexpected benefits.
Remember when Kernel releases were very infrequent "when it's ready"?, moving to a much more frequent release has resulted in a much more reliable kernel, as well as drastically increasing the development speed.
Mark raises the question "could they make releases more frequently", if they can continue to drive down the time between releases, at some point it becomes indistinguishable from a "true rolling release" I put the ultimate limit at 'daily releases', but realistically, if they made 12 releases a year (with good reliability and without breaking users), would that be very different from a true rolling release? I think it would be much closer to a rolling release than the current six month schedule
As to the cause of the upheavals right now, far too many projects don't care about backwards compatibility, and the result is breakage. There is not going to be any way to fix such projects other then for them to get smarter, or for them to be replaced.