First off, if you changed the oil before putting it in storage, the condensation or dilution will be minimal for say, a dozen such starts. Certainly no worse than a car driving on short trips in the winter between oil changes. Probably better that, then to have the lifters pounding when you eventually do start the car. Not to mention the fuel system components getting some exercise. Second, when it storage, the car is often back behind other cars so moving those to get to it would be a major production, even if a tire wasn't flat or some other issue that would preclude driving it.