The Io language has both actors and prototype based OO inheritance. Asynchronous messages are implemented using futures. Furthermore: ""When an actor require

The Io language has both actors and prototype based OO inheritance. Asynchronous messages are implemented using futures. Furthermore: ""When an actor requires a reply message from another actor, it is known as an insensitive actor, and will not process any further messages in its mail queue until it receives that reply."" Why must this be so? In Io, the same objects/actors can run other coroutines while waiting on a message. Just because no language happened to implement all of these in the 1970s and does not mean no language could have implemented them. In the concluding paragraph the author does go on to say that it is now possible to do all these, but I disagree with his implication that it is advancements in technology that made it happen. A more likely explanation is simply that programming languages are notation, advancements in notation do not follow the exponential curve of Moore's law, and it simply took this long for people to think of combining all these concepts in one notation.