Well, there is the interesting point that
@Don Durito brought up that if halflings are living deep in human territory, protected by the human lords, that they would have to pay taxes. Which is sort of the case with all the human farmers.
Of course there is also the fact that humans have traditionally enjoyed tasty food enough to go to war over it. A lot. So, halflings liking it more than that, while humans simply stop caring about good food and bow down to almighty gold piece seems a bit strange.
I mean, the argument still is that halflings have special spice plants that can grow to provide them with everything they need, but humans are too blinded by gold to grow those spice plants and instead spend their gold they want so bad to buy spices. It doesn't make sense.