Bodybuilding is about stretching and expanding the muscles you have, muscles dont "split and grow new tissue" it simply doesnt work that way
You have the same tissue when you get at your biggest that you had when you started, they just stretched and expanded
This is why once you stop they go back to what they were before regardless of drugs, problem is its way more noticable with drugs as they expand and stretch more
I still think you can stretch and expand your tissue with pump and stretching workout rather than lifting huge weights
All the pushing past failure is just a waste of time