I don’t know if it is emotions getting blunted or just that having had a much wider range of experiences the extremes needed to trigger strong emotions are much rarer. When you have little experience of food every meal has a high chance of being the best thing you have ever tasted by a strong margin (or the worst!). But eventually you get to the stage where you have tried so many things that the chances of any one thing being the best are slim, and if it is, it is not generally by a wide margin. I imagine that if you could recreate something as dramatically different as your first taste of sugar your emotions would be just as strong.

I believe the tendency to become less adventurous as we age is down to the same thing. The chances of a new recipe being better than the best recipe we have discovered so far gets lower and lower as we go along, until we get to the point that trying new things becomes more likely to be a negative than a positive. But doing this creates even less likelihood of having an experience that triggers strong emotions - which is why some people go to the opposite extreme of chasing adventure and looking for dramatically new experiences.