that's funny, you can tell that to my bro who competes professionally and is damn huge.
and you can try to prove me wrong, because I shot from 140lbs (used to be pretty skinny =[ ) to 195lbs in 3 months with 5% body fat and i'm 5'10 and i am proportional and I do not juice
the muscle does care about failure bc when you hit failure youre muscle fibers have ripped under stress and used all its atp energy, pushing your body back into protein synthesis to repair those protein strands and atp. gaining muscle.
and yah, you do need intensity, you have to work with the intensity to failure.
because if I do just what you're saying, I could just do 1 rep of 300 lbs and call it a day for bench press, the intensity would be high, but I didnt work to failure so it wouldnt do shit