Getting Presents Means Less As You Age?

An article titled, " Why Presents Become Less Exciting As You Get Older" talks about how as we age, our brain's "reward system" doesn't function as strongly as it once did, making older folks less inclined to be excited about gifts than younger people are.
The new study says this is why kids are so excited to get presents, because a chemical in the brain which controls the feeling of reward is abundant when young, but decreases significantly as a person grows older.
I'm always interested to know more the science behind how our body ages, but a part of me has a hard time believing that there's biological certainty we'll all like gifts less as we get older. I don't know about you, but I've definitely seen 60+ year old men gleefully jump up and down for joy when they get a present!