I agree that that is probablyh the ideal scenario but, from experience (both personal and from friends/family), if the kids come from a "stable background" then, in general, it doesn't really matter.
I've seen kids of family/friends grow up from those who spent the first 5 years without nursery and those who spent most of the week at nurseries and they have all grown up to be "normal".
Bottom line: there is no right or wrong way here.
IMHO of course.
edit: fwiw, Mrs Trousers did go back to work after having our two but gave up work after countless times of being told by nursery staff that she had missed out on their "first this, first that". She wanted to be there to witness these special moments.