I have a hard time believing a 40% failure rate.
I have 0 broken GCs, 3 broken Xboxes and 4 broken PS2s.
PS2s are very sensitive to dust, but cleaning fixes a very high percentage of them. Xboxes I have zero success cleaning them. When the disc read errors start, it's the begining of the end. Thought I had my first broken Gamecube. It gave that warning to consult the manual, and the manual said send it in for servicing, so I decided to take it apart. The drive wasn't working. Put it back together the next day and now it works perfectly. I have no idea why though.
In spite of the fact that the Gamecube doesn't sell nearly as well as the Xbox, or PS2, I still feel it is the most reliable out of the current systems. PS2 and Xbox are about equal in my experience.
^w^
Ps. GC controllers are much more prone to break downs, and PS2 controllers are tanks.