It has been suggested a few times on the thread that parents don't leave their children in nurseries where they are unhappy, that parents would know when their children are unhappy and take them out. Well, ime, that is not the case. I think people normalize the unhappiness of childcare and often think that is just the way it is.
When I had ds, there was a baby boom in my uni dept. 10 other women had babies at the same time. They all put their babies in cc, because that was what was done. The phd students put theirs in at 12 weeks, because that's how much leave they got, and the academics at 6 months. Now this was in Australia, where the ratio was 5 babies to one carer. These parents were putting their babies in rooms where two carers looked after 10 babies. They thought this was fine.
Not surprisingly all the babies had trouble settling. The parents thought this was normal and fine. Some eventually settled, others kept having problems but the parents carried on with their 'plans'.
One colleague put her baby in at 6 months. At his second birthday she said to me, 'he's so grown up now, he's even stopped crying when I take him to nursery'. This boy had been crying for 18 months at drop off. His mother thought it was normal.
Another colleague also put her baby in at 6 months. Her child was anxious, unhappy and not suited (IMO) to childcare. At 4 he was diagnosed with an anxiety disorder and speech delay. I'm not saying this was due to cc, just that a boy with these issues probably wasn't being helped by group childcare 40 hours a week.
Another friend had a small son. He used to get bitten and shoved around at cc. This friend told me that whenever she picked him up she would see another colleague's son in the 'time out' cot because he had been naughty. That boy was eventually diagnosed with ASD.
My only point here is that all these children were unsuited to childcare, but their parents never reconsidered sending them there.