(Actually, if any city tried to do THAT, I'd imagine the discussion here would be the opposite and it'd end up in "Your Rights Online" -- "How DARE they force us into a cashless economy! Today it's forcing businesses to accept credit, tomorrow it's no cash allowed! My right to anonymous transactions must be upheld!!!")
I'm sorry, this is BS.
Cabs accepting credit cards doesn't mean that cash-payers are stuck having to use a card. They can still pay cash. No one is proposing to change this. Uber doesn't take cash, but for the YRO people, that's not a problem because it's well-known up front. You just can't even use Uber without getting cashless payment set up through them. It's not like an Uber car is going to show up and drive you somewhere and then you need to figure out how to pay with a card.
The problem with these stupid cabs is that they'll say they take cards, but then when you try to actually pay with a card they tell you the card reader is "broken". It's a case of simple lying, and bait-and-switch. I can't image how any anti-cashless-economy or YRO people would be in defense of this; the libertarian crowd is all about people and businesses having maximum freedom within the law, not for them to lie and advertise one thing and do something else, which sounds a lot like fraud to me. I've never heard of any true libertarians being in favor of fraud.
If the cab companies want to advertise that they accept cards, then they need to do so, plain and simple. This is what people are complaining about: a cab shows up, it may or may not accept cards, they just don't know. You don't have that problem with Uber: you know up front how you have to pay, and you already have it set up to automatically charge you. Uber also gives you a close estimate how much it'll cost up front, whereas with a cab you have little idea, especially if the cabbie drives you in circles or some circuitous route to get a higher fare. In short, Uber's singlehandedly fixed everything wrong with the cab industry.