This has always been something I was curious about, but now as I'm researching building circuits for use as game pieces it's actually a professional curiosity. Specifically swappable, interlocking pieces, so connections akin to how cartridge games worked.
Why were NES cartridges unreliable? By which I mean, why did they take so much effort to get working? SNES and Genesis cartridges by comparison rarely required reseating or odd efforts, like using the another controller to hold it in place.
Is this just a matter of a bad design in the NES that was corrected with the SNES? And if so, how was it solved? Even the NES v2 (top loading version) seemed to suffer from these problems, albeit less frequently.