Here's a view from across the pond, where babies are routinely put into childcare at 6 weeks old. I'm excluding from this socio-economic households where the mom has to earn to make rent.
When I had my babies and for around 11 years afterwards, it would kill me to walk past daycares in the urban neighborhood where I live, seeing teeny tiny tots dropped off at 8am, picked up at 6pm. They'd have milk mostly at daycare, graduate to breakfast/lunch/dinner at daycare, they'd see knackered parents for an hour before bedtime. Often, toddlers' bedtimes would be at 9pm or later just so parents could spend time with their children, parents knowing that an irritable baby the next day, one who has to be up at 6.30/7am, would be dealt with by someone else. By and large, the children had stable and regimented lives with a more or less stable roster of daycare workers.
Time went on. Those babies became preschoolers with nannies, still on similar schedules, still all hanging out together and going to the same classes, and still "acting up" at home with parents because at home with mom and dad was not their normal. It wasn't where their friends and familiar adults were, it was an exciting place where both of their parents were, but parents who attempted to discipline them but also didn't want to waste precious time "being mean", parents who tried to ask them questions about their lives they weren't equipped to answer.
Often, moms (it was ALWAYS the moms) would co-sleep with their children until they were 5 or 6 years old. I only discovered this when these children approached the end of elementary school and had been in their own beds long enough for the parents to feel comfortable sharing that type of detail. It was to stay closer to them as long as possible.
Fast forward to 13/14/15yo, and - much like the FF vs BF debate - put them in a line-up and you can't tell these kids apart from kids who were raised by a SAHP (where I am, the split is about 70-30 mom-dad). However, delve a little deeper and often (not always), the relationship between parent and child is...odd. The child now knows it was put in daycare, the child has tremendous intellectual and emotional independence from its parents. It's a different set-up, not better or worse necessarily. And it's created children who's understanding of relationships doesn't always center the nuclear family.
On the other side of the equation, you have moms who've kept their place in the workplace. However, they're also ALWAYS the ones hiring and managing nannies/ babysitters/ cleaning ladies, doing the shopping, doing the planning, doing the school interaction blah blah blah. They're EXHAUSTED and constantly, CONSTANTLY having to choose how to parse out their energy. There is always someone they're letting down, somehow.
I don't know what's better for the children, but the answer to the gender pay gap isn't to put babies and toddler into daycare so that women can continue running as fast as men like pregnancy and motherhood is a distraction that can be ignored. IT'S TO FUCKING PAY WOMEN THE SAME AS MEN, and appreciate that all parents have to make sacrifices. It's an attitudinal approach in the workplace, but for as long as the workplace has at the top of its structure men who are facilitated by women (and the rare case of the reverse), nothing will change. There's not enough to go around, and women are definitely paying the price relative to price, and for me the jury is out on whether the kids are paying a price too.