I don't see why it's such a big deal for somebody who never gets a present from somebody else to opt out of the gift exchange. I mean, isn't gift "exchange" the point? Haven't people posted on the boards about giving presents to somebody year after year, and never getting one, and deciding to cut back on gift-giving? It's not so much that one prefers giving to receiving, but there's a difference in giving something to somebody because you heard they were interested in it, or saw it in a store and thought it was perfect, versus "obligation" giving when you know that a holiday/birthday is coming and a gift is required, so you try to figure out what the person would be interested in and whether it's in your price range. Why is it so foreign to say, hey, I'm going to a lot of trouble every year to get presents for every other family (okay, it's just for the kids, but the parents benefit), and yet nobody does the same for us, and we feel left out?
I rather wonder how much say Ted and his wife got in the switch to presents-for-kids only.
My brother and I don't exchange presents for Christmas, because he's single (well, just got engaged!), and I'm married with 4 kids, and it's just really hard to make it reasonably fair without undue burden on one side. It works out really well. My BIL and SIL, on the other hand, have 3 kids, and so it works fairly well to do a "kids only" exchange with them because it's fairly balanced.
I realize that it complicates things more when there are more than two siblings, thought. Three of them want to do kids-only, and one would prefer not to. It makes perfect sense to me, then, to have the childless couple opt out. Depending on the situation, they could maybe give a present that would be to *all* the kids, like a game they could play. But that would only work if Christmas was, say, taking place at the grandparents' house, and all the kids would come there regularly to play, or something. Otherwise, what would happen to the game after Christmas? Or they could maybe get a Christmas ornament for each kid. But otherwise, yeah, if I were one of the families with kids, I would totally understand them opting out and would support them in it.