Interesting post from WoW general forum.

[Malakar]

... You see, anytime you update code on a system, new bugs are introduced because either the bug was lying dormant and required some new code to come out or the new code clashes with some aspect of the running code and brings about the bug.  Then we have other issues that crop up due to advances in the workstation hardware that can bring about still other bugs.  In essence, the more you add to the system, the more complex it becomes and the more complex it becomes the easier it is to break somewhere which then requires manhours to go back and find what broke and fix and *hope* that your fix doesn't introduce another bug somewhere else.

You go to explain how bugs/problems are introduced when you make changes to a system, in response to a quote which contained "assuming no core system changes are needed."

The technology behind clustered servers is very much more complex ...

Irrelevant. What is being discussed is whether or not these servers can eventually operate smoothly with little need for babysitting. That has absolutely nothing to do with how complex the system is. How complex the system is relates to how long it takes and how hard it is to make it smooth, not to the possibility.

Of course natural disasters like tornadoes change things, but they'll destroy any system anyway, and are kind of out of scope.

By the way, I'm getting the feeling of an implication that normal servers/PCs aren't complex, which is absurd. Perhaps you might want to learn assembly, or maybe even delve into hardware design.

... and it isn't simply similar in anyway.

I was under the impression that these servers ran on silicon chips.