That's a good observation, though I'd say here that two things could be true at the same time. But, I do personally believe that most of the reported nerfing is the case of your chart + latent evidence-less complaining. Honeymoon phases are real.
You can't just dismiss something backed by careful measurements by throwing a truism at it. What is this honeymoon phase? Can you quantify it? If not, how are you sure it's real?