All cartridge-based systems are just like that - you learn to live with it.
about:
5% of Atarti 2600 games
95% of NES games
80% of Genesis games
30% of SNES games
will not play without being cleaned first (isopropyl alcohol solution). And I don't just mean they won't play the first time, and then they always play after they're cleaned. I mean every single time you pop the game in, whether it's been played recently or not, those stats apply (and I have over 100 games for each system, and more than one of each system, so the stats are fairly reliable).
They also have those special cleaning cartridges that you can use to clean the system-side of the contacts with. They're quite a bit of manual labor to perform the cleaning though, and I've found that they usually don't help much anyway. Usually games still won't play, you have to use the isopropyl alcohol.
They do have replacement cartridge slots that you can buy for most systems, and the pins are much tighter on them, which helps reduce this problem.
The problem is simple oxidation. Even if you don't play the game, just sitting on the shelf, the metal layers oxidize. And when you play the game, they oxidize faster due to the ionization from the current going through the contacts.
If the oxidation is really bad, and a cartridge won't play even after cleaning, you can use an eraser to really rub the heck out of the contacts until it will play.
In rare cases, I've found cartridges that actually died. So far:
3 atari 2600
1 Genesis
1 SNES
I haven't had a system die yet, but I have several Genesii were the power and antennae inputs have been loosened from being yanked by careless previous owners, and now will reset if you touch the cord (FYI, these ones were not put up for sale).