I think it is possible but each economy would be different depending on the resources it owns... There is no way all economies would be equal, but they could all be developed to an extent. I feel like this is happening right now with the US. It has basically stalled out with all of the outsourcing of jobs while other less developed countries "catch up". At some point the entire globe will be close to one another in terms of development... Then the deciding factor will only be resources and population...