The ability to reverse a charge isn't just about helping you if you are cheated by a merchant, though. It is also about if your credentials are compromised and used by someone else.
Sure, you might be happy to give up your ability to get a chargebacks against a particular merchant.... but what about against a thief?
It's a tradeoff - in a number of cases, I would be willing to accept that risk. I already do with cash.
I would be happy to have a way to pay merchants I trust online with and remove the ability to reverse the charge if I was financially incentivized to do this (with the money the merchant saves on fees).