Birth rates fall in industrializing countries due to many reasons, including improved infant survival, access to effective birth control and the rural-to-urban movement of populations. The education of women, in particular, closely correlates with falling birth rates.
I don't know anyone who limited family size due to Malthus. Certainly, stagnant incomes have made large families difficult. Economies that necessitate two income households have also inhibited family size.
Most past migrant families in the U.S. were large, a custom which changes over generations: Chinese, Italian, Irish, Dutch, German....
Hasidic Jews and 'Quiver Full' evangelicals have ultra-large families and look to gain political clout from them. The Amish go big--for the farms?--and seem unconcerned about votes.
You worry too much about the oddest things.
"If you can keep your head while those around you are losing theirs, you can collect a lot of heads."
Homo sum, humani nihil a me alienum puto.
-Terence