DislikedSorry to ask this, but are you serious?
You let the EA do the job for you and you are always profitable in the long run?...
I guess lots of people will send you PM's asking you about that, and you will answer with a price, right?...
Man.. come on.. Let's be honest, we are all trying to learn here, why always we finish with that kind of subliminal PROPAGANDA...
Of course, it's not easy to create and test such a system. For starters, read this excellent post by topherhk88. You will realize that building a successful completely mechanical system is a tedious procedure.
So, assuming that you have several profitable systems, backtested over many years, with a historical (or Monte Carlo simulated) drawdown that you can accept, that those systems are mostly uncorrelated so that the probability of them stopping working at the same time is small, that they work or at least survive during all market conditions (trending/ranging, volatile/non-volatile) and that one system's weak period is another system's strong period, then why not make an EA out of those systems ?
You could even make it stop trading any sub-system that exceeds maximum historical drawdown, and re-start trading that system when it shows profits again.
Now, if you think that no system can show consistent profit over several years (and even decades), then you might want to do a little more backtesting.
ETA: I will acknowledge of course that the vast, vast majority of EAs for sale are total crap. People who have made solid, thoroughly backtested EAs with acceptable drawdowns, will not sell them. Certainly not for 199.90 or even 9999.90.