Why can't I add more ventilation to the wind turbine? Will that not solve my issues with humidity?

By adding more ventilation, you will have the same humidity inside the turbine as you have outside. It is known from various studies that the humidity needs to be below 60%RH, to stop mould from growing. Most of the electronics works the best at a low humidity. Further, corrosion is also slowed down at a lower humidity than 60%, therefore it is better for the asset to have the humidity removed than just added ventilation.