Single-payer healthcare systems ensure coverage for 100% of citizens. This reduces the total cost through administrative savings and cost containment, as well as through access to preventative medicine.
Hospitals would no longer have unpaid bills, collection departments, or highly involved billing systems, all of which would add dramatically to savings.
Small businesses and start-ups would be able to offer the exact same coverage as large corporations thus leveling the playing field for small businesses.
Large, frugal corporations like Walmart would no longer be a drain on the tax base, as they'd be covered just like everyone else.