The Simpsons are contracting as part of their life-cycle towards relevancy.

Art imitates reality but only for a short time. Eventually all memes, stereotypes and cultural references phase away. Keeping those things similar or stagnant is impossible in chaotic environments.

Case in point, the mob is no longer as prevalent. Germans barely eat as much candy and the pizza guy, well he is angry!

Only death remains the infinite OG-OC meme! Now who wants to challenge t3h grim reaper?