Those folks also lacked the internet, where ordinary people can look up extraordinary things that previously could have only been learned by a select few privileged people, if at all.
We also have a global economy of a sort that did not exist previously. Things that would have been exotic not that long ago can be acquired readily by people who aren't wealthy by first world standards.
People used to routinely suffer scurvy, which is almost unheard of today because a) we know what causes it and b) ordinary people have no trouble getting citrus fruits. This was not true, say, 200 years or so ago.
And global access to non-native food sources exists since the 15th century.
The difference is whether mostly everyone has access to it.
So yeah. I'd say he's right and I'd bet your fancy shmancy genetic engineering won't wield anything significant but for a residual percentage of very specific cases.
As has most medical technology. The overwhelming majority of diagnostics are still made via question/answer, palpation and hearing.
Mass promiscuity has consequences, just like poor sanitary habits have them.
