Why doesn't copper react with nitrate salts?

Copper reacts with nitric acid according to this equation:


$$\ce{Cu + 4 HNO3 -> Cu(NO3)2 + 2 NO2 + 2 H2O}$$


This is a redox reaction with copper getting oxidized, and nitrogen getting reduced. If we think of the $\ce{H+}$ as a spectator ion (which I know is not exactly right, since it forms covalent bonds in water in the products), then you would have the following net ionic reaction:


$$\ce{Cu + 2 NO3- -> Cu^2+ + 2 NO2 + 2 O^2-}$$


I'm wondering why this reaction doesn't happen with solutions of nitrate salts (like $\ce{KNO3}$, for example). If nitrate is such a strong oxidizing agent, shouldn't the dissolved nitrate ions still be able to oxidize the copper, even without the $\ce{H+}$ around? It wouldn't be able to form water as a product, but should be able to form hydroxide ions ... something like this:


$$\ce{Cu + 2 KNO3 + 2 H2O -> 2 KOH + Cu(OH)2 + 2 NO2}$$


Is it just that forming water is necessary to make the reaction favorable, or is there something else that I'm missing about the process? (Maybe something in the mechanism where the H+ speeds it up?)


