I have never had any console that has failed on its own from a manufacturing defect in ~25 years, dating all the way back to the Atari 2600. I've owned about 15-20 different systems in all over the years. I still have a few of them too (the 2600, a ColecoVision, a Sega Master, a Genesis, a Panasonic FZ-1 3DO, N64, and launch PS2) and those all still work perfectly today.
I have replaced a console once though, and that was an original NES. Totally my fault, too, because I took it apart trying to figure out what the heck that expansion port on the bottom was for, and I accidentally shorted it in the process. I was probably 13 or 14 when I did that. That failure was 110% user error though. It worked fine, and the replacement worked fine too. I never used the Galoob Game Genie either, which was the major culprit in killing NESes back in the day. Every single person I knew that used the Game Genie screwed up their 72-pin after around 1-2 years of using it.
