Why are we all paying a tax to credit card companies?

It's fat times for credit card companies. Visa made $10.3 billion in profits in 2018 on just $20.6 billion in revenue, up from $6.7 billion and $18.3 billion respectively in 2017. Profits were up again to $3.0 billion in the first quarter of 2019, a 14 percent increase from the same period in 2018. Mastercard, meanwhile, took in $5.9 billion in profits in 2018, up almost 50 percent from 2017, and saw a similar 25 percent jump in the first quarter of 2019. Beyond that, individual banks...