Very difficult issue. The cost of living and childcare is so high that parents don't feel that we have much choice but to return to work (I'm definitely in that category)and there are always times that you will need some emergency care or a more permanent arrangement. I know grandparents who willingly do a day a week but it sounds like some are doing a lot more.
Comes back to some basic issues - more parental leave, heavier subsidies for childcare (20 hours for 2 year olds would help) and higher wages to assist parents. Just has to be a cost that society bears if we are to raise happy kids.