Indeed. People also like status. If consumerism ties status to consumption, then children constrain that consumption and thus constrain status.

It also used to be that having a large family was a source of honor. Today, it makes people uncomfortable. They may even take a condescending view of those with many children. People have formed a strange association between having many children and poverty.

What you find is that the highest fertility in the developed consumerist world tends toward the poor and the rich. It's the middle class that has the fewest children. This makes sense through the lens of consumerism: the consumption of the rich is not constrained by having more children, while the poor can't consume all that much anyway, so having more children doesn't really change their buying power meaningfully where conspicuous consumption is concerned. It is the middle class (especially the upper middle class) that is anxiously keeping up with the Joneses and engaged in aggressive and petty consumerist competition. They have just enough to consume conspicuously, but not enough that they don't need to prioritize their spending. Consumerism simply prioritizes conspicuous consumption to the detriment of fecundity.