Absolutely not, the fact that the robber does not have actual physical possession of the fruits of a crime means nothing. Maybe the robber has already got rid of the stolen property by selling it, hiding it, pawning it, or even throwing it away in the garbage. If law enforcement authorities suspect that you are the robber, they can arrest you and charge you with the crime. If the government can prove that you are the robber ( ie., surveillance tape) you can be convicted.
For example, say you went into a bar and told the bartender to take the money out of the cash register and put it in a paper bag or hand it to you. At that very moment, you decided that you really shouldn't do this act, turned and ran out of the bar. You are still guilty of robbery even though you never touched the money or the bag.