In theory yes, but in reality even if you are trading an automated system you may at some point get an issue with fills which you wouldn't during demo or backtesting.
The reason so many do well demo trading and not live is simply that with demo trading you do not have real money on the line and hence you don't have real emotions.
When you have your own money at play things can get very different. However if you persevere you should hopefully get to a point where you can do similar things live as you demo.
