That was my direct experience as a kid growing up in a non-Western society (I'm 40 now, am from Eastern Europe). When I first read about the Western tabu of parents not being allowed to sleep in the same bed with their children anymore I was a little surprised at first, and then saddened for those kids: "do you mean 3-year or 5-year old me should have slept all alone in his bed at night with no parent close to me? That is pure madness!"
More than that, one of my most vivid memories as a kid was sleeping with my brother and my two grand-parents in the same 3x4 meter room (give or take), my brother with my grandma and 6-year old me with my grandpa (there were two beds, a stove, a TV set and a small table in that room). I can still remember my grandpa peeling apples or pears and sharing them with my brother and me, just before we all went to sleep while we were watching some TV, very, very nice memories (in fact my nickname is taken from a Soviet TV series we were watching then [1]). Afaik neither me, nor my brother (who is 2 years older than me) were making any unwanted sounds while we were asleep at night.
I was more generous in how I interpreted the article: the need for sleep-training is a consequence of the child having a whole different room to themselves. Parents in other cultures who share the room (or the bed) do not get the same level of extreme sleep deprivation and, as a consequence, will not need to sleep-train.
To me, the article is not questioning how good the parenting in the west is - it's contrasting it with parenting elsewhere (and tracing the roots of the parenting practices)