I really don't think that's true; there are plenty of merchants who do still charge different prices based on payment method. But there are also many who voluntarily don't, because the actual cost is negligible and better than the alternatives. Regular bank transfers of various kinds between consumers, including iDeal internet payments, as far as I can tell, have no fees at all. Cash withdrawals across different currencies may incur fees, but I've never seen fees in regular Euro cash withdrawals.
Nobody here is charging 2-3% except when credit cards are involved.
