A year isn't really enough time to change over a business model.
Eh, Kroger killed Visa credit acceptance at a couple of their brands with a month or so of notice, so I'm not sure I buy that.
Rewards cards were a direct response to the Durbin amendment. The Durbin amendment allowed consumers the ease of a card based transaction but gave the banks only about a thirtieth of the interchange fee they were getting for credit cards because debit card transactions are secured. Rewards cards were a way of encouraging consumers to use credit cards rather than debit cards because there's a little something in it for them.
Rewards cards have been a thing since at least the late 80s.
In fact, the next wave of innovation began in the early 1980s with airline frequent flier programs and credit card loyalty programs. In the late 1980s, credit card issuers began introducing a broader array of loyalty and rewards programs. In 1986, the popular “cash back” program from Discover Financial Services, a division of Morgan Stanley, appeared. Discover introduced the concept of providing cash to the credit cardholder at the end of every year based on the total amount of charges. Such programs are still in place, three decades later, and remain highly popular with customers.
Did Durbin help inflate the amount given back to cardholders? Maybe. There are also other factors, though, like millennials being more credit averse than their parents (and thus less likely to use credit without an incentive) and the improving economy.
Reward card interchange fees are about twice that of standard credit cards an are about 60 times the fee of debit cards.
Some debit cards, specifically from major banks. The smaller ones don't have any caps.
charging different prices for different credit cards is probably more than consumers will take.
It's also still against card network rules, for now at least.