OK. Some of you are either going to think this is a STUPID question or a SMART A** question...

I have the same problem that a lot of people seem to have with my CA glue drying out in the bottle. I've heard, many times, that some people recommend storing the bottle with the cap OFF as the glue cures in the absence of air. Therefore, if stored with the cap ON it will cure and cap OFF will remain fluid. Is this correct?

Now my REAL question... If this is true, how come the glue is not dried up when you buy a bottle? I mean after all, the tip of the bottle is sealed until you snip the tip off. Sorry if this seems smart alecky but I'm confused. Thanks.