Your experience with the AirPort base station is unique, AFAIK. However, your charge that the "only times Apple admit(ted) something outright" is flat-out false. The iBook G3 logic board, certain iMac power supplies, and iMac/eMac problems directly analogous to the Dell situation were all acknowledged and addressed aggressively by Apple.
I've been an Apple Authorized Service provider since 2005. Apple had the "capacitor plague" problem with certain iMac and eMac models. Apple acknowledged the problem, and customers were authorized to come to me for a free repair for as long as three years after date-of-purchase if the warranty had run out. Those repairs constituted a good part of my work from 2005 through the middle of 2008. Every customer--especially the ones out-of-warranty, were grateful. I made a point of telling them that the problem wasn't restricted to Apple machines, and I directed them to the Wikipedia entry on "capacitor plague."
I was on the AirPort team from 1999-2001. I heard not one word about thermal problems with graphite base stations. I did the build acceptance and functional testing on AirPort in the first version of Mac OS X. I also performed automated and manual usability testing with dial-up, my own Earthlink account, and a Graphite base station. That base station worked constantly--day and night--for over a year. It was still working when I left.