I'm wondering are families typically effective when both parents work & kids grow up in day care?

Not especially: From the phrasing of your question, it sounds to me like you have lots of guilt about working full time. This is very natural. There is no substitute for parents spending time with their children as much as possible. But you also need to do what you can to provide for your family, that is also important! Parenting is like a war. Consider one parent going part time if possible!