Nope, that definitely doesn't apply to all applications. What did you do to "test" that? Check the air CFM or velocity actually moving through the radiator?
Having the fan the close enough to the radiator will certainly reduce the need for the shroud depending on the diameter of the fan compared to the surface area of the radiator, but, when the car isn't moving a fan that doesn't cover 100% of the radiator will not pull air across the entire surface area.
Given a specific application I can see how the cooling system wouldn't necessarily need that additional air flow to effectively cool the car, but that doesn't mean you aren't losing cooling capability.