Earlier quoted context omitted.
I would be very interested to read an academic paper that made this point. 200 years is a blink of an eye in almost any vertebrate's evolutionary time. Also, to support your claim, one would need evidence that the child mortality of the past reflected genetic unfitness (as opposed to poverty or the unavailability of antibiotics).
I'm not making a formal claim just sharing my thoughts. Though I do believe at least one evolutionary biologist has written about this: Hamilton W.D. (1999). The hospitals are coming. Narrow roads of gene land (Oxford University Press). Btw the phenomenon of 'mutational meltdown' is a closely related topic and may re-pay googling.
http://wasdarwinwrong.com/korthof97.htm
I would guess it is wrong; we are on a track where genetic manipulation to treat blatant defects will (relatively shortly) be cheaper than the traditional medical treatments.