I'm sorry I mentioned SG's case, because you seem to have extrapolated it in some slightly weird way as minimising what faces them, because I have watched to much banged up abroad. I have of course watched too much banged up abroad but I have also been inside SAm prisons and worked a lot with Latin American drug traffickers/mules, translating for them. SG's ordeal was much, much worse.
The women's prison in BKK has never been comparable to the men's prison in terms of conditions. Thank god.
I think you are focusing exclusively on the relative conditions, and overlooking the entirely different set of circumstances in your equation when you use SG as an example to illustrate your point.
Had she been just out of her teens, naive, newly arrived as a tourist with no language/cultural knowledge or skills, devoid of a long standing (and reporter avoiding) local support system during the particularly hard transition phase (when the realisation that this is real, and it is going to happen, and there is no magic wand in consular hands to magic it away hits) then she would be more comparable with the case in hand.
But then, had her circs been so very different from what they actually were, even if the prison conditions been somewhat less awful, I don't believe you can reliably predict that her outcome would have been much the same.
I am not convinced that "well the prison isn't as anywhere near as bad as the one in BKK" is any indication that the albeit better but still "culture shock with knobs on" conditions in Peru will automatically fully compensate for the entirely different set of circumstances. I think having a basis of "better the devil you know" is something of an advantage. SG went as far as to state she regretted being moved to British prison, despite the "on paper" improved conditions.
I don't think there is cause to believe that this is going to be the inevitable death of any kind of future for the 2 women in Peru. People can and have come through similar and gone on to rebuild their life.
But at the same time I don't see how anybody can feel reasonably sure that in the longer term it doesn't pose a significant risk of being the catalyst for a downward trajectory.
I think perhaps the 2 young women who got banged up for drug smuggling in Thalland after Sandra (I think they were in at the same time, was one of them was called Holly ? ... I'm fuzzy on the details but weren't they tourists and around the same age as the 2 in Peru? They got a royal pardon or got sent to serve their sentence back in the UK relatively quickly I think ) might provide a better "comparable example" of possible outcome. But I have no idea what happened to them. And it's hard to google when you can't even remember their names.
If I had to pick for myself between SG's circs + women's prison in BKK and the circs for the 2 in Peru + less awful prison in Peru, I'd pick Sandy's lot.
Thailand is familiar to me. Peru is not. I'd take worse conditions over the the greater fragility of my 20 year old self and a complete ignorance of language and customs that exacerbates culture shock at the best of time, let alone the worst of times. In terms of long term future/happiness survivability I think the former has the edge in terms of a better bet than the latter.
I tried to do the above using what as a parent I'd pick (if I had to) for my son. But even in the hypothetical I broke out in a cold sweat. Whatever the outcomes for the detained I have no idea how their parents get past the experience in one piece.