All systems will fail at some point. Drawdown is based on the size of the sample. Larger the sample, larger the drawdown. The key is what you do with the money while you have it. You know that at some point with in the next 5-10 years the account is going to go on a slide so just take out profit at regular increments. That's how you win in the Expert Advisor world. I've got a system that lasts 10 years finally, but the thing is, if I didn't pull any profits along the way, it would have only averaged 10% annually.
I code in logic to stop trading at double my deposit. So, for instance I deposit 10k, system will bounce around and when it hits 20k I'll stop and pull my chips, then repeat. At some point it will have to fail, but hasn't in last 10 years, so I should keep running it until I see smoke.