I kind of agree with OP that most mothers who use childcare for very young children aren't doing it because they have no alternative. Childcare is so expensive that financially it doesn't stack up for the lowest paid anyway. With the exception of single parents who get universal credit to pay for most of it.
I think plenty of mothers prefer to work than stay at home all of the time, for lots of perfectly good reasons. Including career progression, a better standard of living, retaining financial independence from their husband, status, job satisfaction, boredom from staying home, needing a break from demanding toddlers, not enjoying household chores, etc. None of these are wrong. It's ok to make a balanced decision for the family rather than to put your child first 100% of the time
The idea that the mother looks after the child all of the time is a new one and not something that has historically happened (except maybe for a brief period after the war). It's totally normal for other people to help with childcare and even to be paid for it.
There's good and bad childcare just as there are good and bad parents. I don't think full time nursery is Ideal for any age child simply because they are in one room in a very restricted situation, which if it is 8-6 5 days a week is not great, but using some nursery hours or a childminder is not inherently worse than being with a parent or grandparent.