Another factor that could influence type of attachment and well-being later in life is economic status. If a family is more affluent they will be more able to provide care to the child, such as with a babysitter. The well-being of the child is more likely to be better because the family can provide healthcare, food and shelter.
I feel like this doesn't entirely relate to attachment. You can argue it another way and say well because a family can't afford a babysitter, the child will form a secure attachment to the mother. And on the other hand a well off family's child may not be able to form that attachment because that child has not entirely been brought up by the mother.
I don't entirely agree with this view. I think it is perfectly possible for a family with a poor economic background to raise a child who will do very well in his/her life as long as they provide him/her with proper motivation and encourage him/her to do well so that they can as a family have a better life style. In fact poor economic situation can often act as an incentive for the child to make something better of him/her self in life.
I think in this case you need to consider that being rich does not always mean a better upbringing! The first reply makes a very good point about this economic standpoint. There is no doubt that this has an effect, however at whatever economic class you are at, positive and negative effects can happen.