backtesting cannot guarantee that a trader will be successful in their trading. because it could be that the strategy can work very well on historical data but fail in the real market. but that is much better than traders who only trade based on their luck.
Yeah, backtracking got its own limitations. I do hear that people do say that old strategies are not handful anymore. It is because volatility and market movers are not same for all the times. Backtracking may help to understand on how a strategy might have worked for the past market conditions and if same kind of market occurs in future as well then those strategies may get us profits; still the chances are only 50%. Historical data is a good way to analyse the market behaviour but got nothing to do with profit making.
Where did you get such gloomy statistics, where only 1 out of 10000 becomes a profitable trader? In fact, according to research, about 5-10% become those who profit from trading, that is, 5-10 people out of 100 succeed in trading.
I do not need any statistics for this. In my observation, even out of 1 million trader, none gets opportunity to make consistent profits. Those 5 to 10% may make profits but in long run, they also lose and quit. By considering the consistency factor for long period of 10 years or 20 years (usual investment time frame), you can find less than 0.001% do get succeed in trading.