The network fees that are charged and properly assessed to acquiring banks and payment service providers represent a very small part of the transaction. They're also publicly posted, publicly available, and they've been largely stable for more than a decade.
For Visa, that's 0.09% on a transaction, which is significantly below anything you would see, for example, in the fees that are charged to a merchant by their acquirer, which in fact make up the bulk of the cost for any merchant.