Credit cards need to have personal connections with businesses since it is about mutual trust. A business doesn't want to deal with a shady credit card and credit card providers doesn't want to deal with shady businesses.
So you are talking about a technical solution to a social issue, that wont solve it.
Online pay providers show that it is very well possible. There are tons of payment providers which are widely supported. The only difference is that some of them have a physical presence while others do not.
With a common standard, the available of card-based payment providers would indeed increase. In europe, you often can't pay with Diner's Club or American Express. If they would not all have proprietary systems and were compatible, then their adoption would in-fact increase.
Naturally, not every grandmother and their dog should be able to use this standard but there must be a well-respected authority behind it. Taken to the extreme and we couldn't trust anybody we couldn't have root certificates.
Mutual trust doesn't scale. You really think that either Visa or Mastercard has a personal connection to every grocery store that accepts credit card payments?
So you are talking about a technical solution to a social issue, that wont solve it.