I'm too young to remember this particular promotion (though I certainly ate a lot of fast food in 2004). Data grabbing can't be the only reason, though. It's so much more expensive now to pay a large staff at a restaurant that isn't busy most of the time. Raw materials are more expensive, labor and benefits are more expensive, and the result is a combination of higher prices and lower quality outcomes. If the outcomes were the same the prices would be quite a bit higher.

The only counterexample I can think of is In-N-Out, which is always packed with customers and always has a large and very busy kitchen staff.

TIL there's burgerschachteln.de, because of course there is a person collecting burger packaging on the Internet.

That brought back some memories. I would always order a Filet-o-Fish which they made fresh due to the low demand.