Correction-
The H+ Ions are NOT hungrier than Iron in most reactions.
It takes a catalyst or an enzyme to make them so.
However, water and iron don't make rust, either.
Pure, sterile Iron dropped in sterile distilled water, at normal temperatures, will just sit there. It won't rust.
Another agent is required to initiate the rusting process.
Most rust is either biological or galvanic in origin.