With all due respect, you get what you pay for.
You're paying for superior one-on-one prenatal care, someone with experience, knowledge, and training to be there during the birth. Someone who can handle emergencies, can spot potential problems and advise you in a timely manner. Superior one-on-one postnatal care, breastfeeding support...midwives do a heck of a lot and their services are worth. every. penny. for your wife and your unborn child.
Why in the world would you question why they would price their services at fair market value? What about your salary?
You say your wife has insurance available through your work, but it is costly. Isn't your wife's health worth the cost, seriously?? I would suggest you take it. Homebirth is, by law, covered by insurance in NYS.
What about your child? Will you deny him/her healthcare after he/she is born?