Thats similar to me paying more to purchase a single gallon of milk at Sam's Club, or buying a dozen. You buy in bulk/large quantities, you'll get a better deal. The 'small' ISPs wouldn't have access to information on what the 'larger' ISPs pay, as it would be confidential information.
No it's more like a HOA buying milk for an entire subdivision and saying you have to pay for it even if you're lactose intolerant.