I read that this morning, and I can see her point. Now all of us, including Carolyn Hax, agree that indifference doesn't excuse people from at least sending an email or making a phone call.
But Stuff is so easy to get. For instance, when my mother was a teen, a triple scoop of ice cream was only 25 cents, but she had to babysit 4 hours to earn that cone. I could earn the price of a triple scoop cone in two hours. With many babysitters today earning $10 an hour, that triple scoop is within your grasp in less than an hour. If the parents go out for dinner and a movie, the babysitter can buy a new t-shirt to replace the one stained with melted ice cream from that triple scoop. A adult paying payroll taxes, car payments, rent, and other bills has less disposible income, but most small items can still be easily bought used, if not new.
Then as Venus 193 pointed out, there are more gift occasions, as well as more people buying gifts. I got Christmas gifts from only one aunt, even though both parents came from large families. The one aunt had no children; everyone else had 3 or 4 kids of their own. My great nephews get presents from me, their in-law aunt (my brother's widow), their grandmother, their other grandmother, a close friend of the family, and of course, their parents. They would probably get presents from their father's sister if she had any money. Heck, they might even get presents from their other great-uncle if my family actually got along -- or maybe not, Brother is kind of cheap.
And that's just Christmas.
The point is, with all of this Stuff pouring in, it is too easy to take it for granted. If the parents don't push, the recipients don't care. My Nephew and Niece-in-law do care; they make sure the boys thank everyone. So they keep getting gifts. Another niece didn't care, never acknowledging gifts for her son or pushing him to acknowledge them. I don't send gifts to them anymore.