Ben Johnson was using winstrol when he got busted for steroid use, but he trained as well. Supposedly he was squatting well into the 600s for reps but I dont recall the claimed dose he was running.
Steroids by itself will do only so much, training and diet come first, the gear is just a supercharger if you will.
Since steroids make you "superhuman" then going off them will remove some of your gains yes. However the idea behind using is that you hopefully dont lose but a small percentage of those gains.