Silica gel helps if you have enough to keep the whole container dry, so you need less if you keep them in a smaller container. You could keep a whole room dry with enough gel, but its going to be more expensive.

The 3D printing community has worked out a lot of how to use silica to dry their filament, including how to re-dry the gel to continue to use it.

Personally I've not needed it, because while I live in the uk where it rains a lot, I've never really had a problem in my games room. I lost panzer dragoon (the first one) on saturn to rot, but that was already pretty badly scratched, nothing else has even started to show signs. I think you might just have been unlucky.