Yes, but they also provide services most American citizens won't, like cleaning and childcare and eldercare, lawn care, etc.  Many citizens don't want to do that kind of work - they think it is beneath them regardless of how much you pay.  Ask the next sign guy (you know the ones - claim to be vets sitting at an intersection begging for money) if they'll mow your lawn for $25 (it takes me, a 5'2" woman, an hour so $25 is a goodly amount).  No one has ever taken me up on the offer.