They were mostly bought by middle-aged women, I think; true crime skews younger (or at least the type of true crime - serial killers / procedural or analysis focused stuff skews younger, drama-based 'dirty john' type stuff for older women, also again stuff with kids).
A Child Called It & Angela's Ashes were american so they weren't so huge over here, but they did spark a (still existing) subgenre of like east end victorian / WW2 hard times community pulls together to survive type stories, which seem a bit less dark than the alternative. But also slightly later, Philomena (which I believe is mostly true with some fudged details) and the Magdalene Laundries.
That said now that I know how many of the million pitiers are older women ... who knows.
There was a similar wave of books post-WW2 of holocaust narratives of which many were fake, probably inspired by the Anne Frank diary: a famous one was of a woman who said her parents were deported to the camps, but she escaped the warsaw ghetto to be raised by a pack of wolves. She wrote a book, was guest of honor at a variety of memorial events, and was due to appear on Oprah before it came out that it was all fake. Misha DeFonseca.
She was the daughter of (non-jewish) parents who had been members of the belgian resistance, but who were captured and her father sold out the rest of their cell / branch under torture. She was sent to live with her grandparents, who abused her for being the 'daughter of a traitor' and she did eventually run away from them. She now claims to be mentally ill and unable to tell fantasy from reality, but netflix did a documentary on her which is skeptical - after she went to the US she really leaned into the 'communed with wolves' stuff and was going full native american about it. The documentary is Misha and the Wolves.
I think we still have people like that - many cows are, many people on the internet are like that, troons are like that - but we're not going to see it in media until a big actual tragedy becomes plausible, like maybe from China with the Uighur muslims. Or being an immigrant boat child. Both would be very difficult to confirm and easy to make sound plausible, particularly 10 to 20 years from now.
The 1995/6 child tragedy books were between the sinead o'connor incident and john paul finally acknowledging the church sexual abuse in 2001, where it was being discussed, children being neglected enough to be that vulnerable or parents allowing it to happen, but not 'confirmed' yet.