On the one hand, 3% cc fees are much higher than what would be set by a competitive market and are only possible with an oligopoly. On the other hand, the convenience that they allow for not carrying cash is often worth more than the 3% to consumers/merchants like me. E.g. any online payment. So while it's massively overpriced, it's still a win win usually, and I think that's probably why people aren't madder about it.
Yeah, the convenience of having drinkable tap water is also worth >3% of your net income. But luckily, because of competitive markets, it's often <0.1% of your income.