Except, I don't believe it is true: at least the way the OP presented it.
In the US, debit card transactions authorized by a PIN have a low transaction cost - by law. Credit card transactions have a higher transaction cost. Debit cards transactions without a PIN are treated as credit transactions.
The fee difference reflects the amount of risk to the bank: a debit transaction requires available FUNDS already deposited in the account. Legally, the buyer also has less protection from fraud.
I would have to look at the law, but I don't believe adding a PIN to a credit card would make it subject to the lower fee.
The reason the US isn't using chip and PIN is the merchants: it would require replacement of point of sale systems. Restaurants in particular can't bring a mobile terminal to the table to complete the transaction. In time, it may happen, but not soon.