The drying out is a function of the volatiles in the ink evaporating. In the ideal case it creates a "crust" on the end of the pen nib which then seals the ink

The drying out is a function of the volatiles in the ink evaporating. In the ideal case it creates a "crust" on the end of the pen nib which then seals the ink cartridge, but in practice air still gets in. When you first open these pins they have a small ball stuck on the end of them to prevent the pen from drying out on the shelf. If you could create a case that maintained an atmosphere that prevented evaporation of the volatiles it would keep the pen from drying out. A 'humidor' keeps cigars from drying out by using a moisture adsorber to keep humidity levels relatively constant in the box. So same principle but applied to pens.