I'm confused by your last paragraph. How does the existence of laws that protect consumers actually protect consumers if the payment systems we use don't allow reversals?
If an ebay seller delivers me a faulty product I can sue them for not delivering what I payed for and when I win the court orders them to pay the money back (plus my expenses). If they don't pay I can go after their assets.
It's basically the same how a business would recover money from a bad supplier. With small claims court it's even somewhat efficient for small sums, but of course still orders of magnitude more work than a credit card dispute.
That's an enormous burden. If we require lawsuits to enforce even minor cases of consumer protection, I argue that there is effectively no actual consumer protection.
The law not working for "minor cases" (which includes cases over hundreds of dollars) is exactly the failing of the justice system I mentioned. This isn't universal, in many places you can get theft of a Mars bar or possession of tiny amounts of drugs prosecuted very effectively, all cases much more minor than the typical credit card dispute.
So, rather than having a financial system with basic consumer protections (which would allow transaction reversals and contestation), you would prefer we have a criminal justice system which aggressively enforces and prosecutes minor offenses? I think there is a weak connection between the two, particularly since most situations where we do things like dispute a credit card charge are civil matters. And, as stated above, requiring civil suits for something like disputing a credit card charge is an enormous burden, and puts the burden on the consumer. (Which will also disproportionally affect the poor.)