What matters is what happens to the water in the atmosphere not the oceans surface. Evaporation requires energy, it cools the surface of the oceans and needs to be driven by sunlight heating that surface, rain is the reverse it heats clouds which then radiate that energy to space.

To boil the oceans you would need the upper atmosphere to retain that moisture or you just get more weather not net evaporation. 1 inch of rainfall represents a shocking amount of energy flow.