Why do beginners when they start working out gain more strength and muscle faster than people who have been working out for years?

Hi, Growth of muscles is a response to pain and the “challenge” presented during the workout. As you get stronger, the challenge presented by the workout is lessened and therefore the response (growth) is decreased. Basically your body is more efficient and therefore requires less growth and improvement to achieve the workout presented. Hope that makes sense. Thx,