The most astute observation I've seen on the topic is that in a capitalistic system in which monetary value is assigned to everything, the value of children is deeply negative and therefore they are not desirable. By having children, most couples are putting their stability, wellbeing, and long-term prospects on the line. The opportunity cost is staggering. If more children is the desired outcome, that tradeoff must cease to exist, and a lousy $2k isn't anything remotely close to that.