The will, primarily, being finite has its limits. Since man is not God, they are not entirely self-sufficient. Man was created weak – he had to eat, drink, defecate, and so on. If at any point man stopped eating, he would have died. Man was not created in an immortal body. There was a reason why God made trees for them to eat off of. Human flesh is inherently weak and in constant need of support. This is why the Tree of Life was inserted into the Garden of Eden: something had to restore man’s frail fleshly body. I’m am confident in thinking that the laws of thermodynamics, namely the 2nd law, (for all you science geeks like me) was in play as much as gravity was. For those of you unfamiliar with the 2nd law of thermodynamics, in simple application, it means that all energy is going from a complex state to a simple state – i.e. all things are burning out. Mankind is as much bound by this law as by the law of gravity, and over time, either man’s sheer ignorance (which they had at the Garden of Eden, e.g., Eve was deceived, and a fundamental element to deception is ignorance) leading him to hurt himself or through some cataclysmic event, man would need repairing. All this to say: even ‘good man’ is inherently weak.
All evidence points towards a mankind that was inherently weak. It follows from the nature of reality, that if you are not God, then you are weak. No matter how much power a creature is endowed with; whether that be man with all their capabilities, angels with all their illustriousness, even Lucifer was given power beyond all imaginative categories, and yet each creature is has an inherent weakness.
If man had infinite strength of mind then to pose that they could bear up under temptation would not be far fetched. But any clearheaded human being would know that this is not a plausible postulation.