> significant costs to provide

3% of transactions is an incomprehensibly large amount of cash. The systems that exist to transact cash have been in place for decades already. Major countries have already developed their own payment systems because they understand the problem and the cost to society. Most of these are entirely free and AFAICT, they work just fine.

> for example by competition

Sure, if you set up a time machine. Even in that case, there would be no meaningful competition. Someone else would simply occupy the position in the middle of the intersection instead.

"Parasitic" and "toll collection" remain accurate descriptors. What about "entrenched" and "monopolistic"?