Bardsandsages said:It depends on how magic is used in your world. A spellcaster can only cast a set number of spells per day. Crafting magical items consumes time, resources, and life force (XP). Therefore, in all likelihood such items would be extremely rare, not common. If I as a spellcaster have to chose between crafting Bracer of Armor to save my hide or a child-proof ginzu, I'm probably working on the Bracers.
Also, magic items are expensive to the common population. Adventurers have money, but the average farmer doesn't have any. The target market for certain items (such as your knife, for example) couldn't afford to buy such an item. And I can't think of many adventurers who would bother with it.
Gold Roger said:I always like decking out my players in travel cloaks from the Magic of Fearun.
They give continous endure elements, are watertight, provide a travel ration trice per day, include a flask that pours hot tea or cold water at will (though the total amount per day is limited) and once per day they turn into a comfy one-person tent.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.