Random Preflop Frequencies Question

[BKiCe]

i don't understand the assumption "well, he 4x'd, therefore he is gonna stack off almost always" - on what basis do you guys make this assumption? i would expect villain to fold to our raise at least 75% of the time if not more - am i way off? seems like i used the thinking "well he's 4xing it he is def coming along for his whole stack" about 3 months ago, never got any action when i reraised 4xers, and completely abandoned that line of thinking