"She boiled elbow pasta from Kraft, measured an identical amount of white cheddar cheese as was in the Kraft packet, added butter and milk, and then... “Whoa!” was the summation of her first bites."

I've done that too, with cheese powder from Amazon. It does seem incrementally better. If there's a "secret ingredient" to macaroni & cheese, it's just the cheese powder which you can readily buy by the pound, and then use for other things. Like putting it on your popcorn (add onion powder to really round it out).

The nice thing is that you end up with a lot more versatility when your cheese powder isn't confined to a Mac&Cheese container. I also like to use it as part of cheese sauces for broccoli and such. It's not a staple in my kitchen, but I probably manage to go through a pound in about 6-9 months, and it still generally tastes good even at the end.