For the most part, the current cards payments system are already very convenient and fast for in person

The frictions you mentioned are mostly not a technology issue.
e.g. US banks taking its time to move towards EMV.

In addition to Credit Cards, there is Debit Cards that functions both over the ATM network for cash and Visa / MC / Discover / AMEX network that allows you to shop in person and online. And now even Prepaid cards that are designed to replace your regular bank account.

After the Durbin act, debit card interchange rate now are in the 0.05% range.

I do agree that online shopping could have been easier. The process can't be shorten too much though as anything that needs to be shipped, even if you don't have to key in that 16 digit card number, you still have to key in a shipping address.