Yep, that’s the million dollar question!
So anecdotally we know that 95% of retail traders are losers. Now of those some chunk are those that quit in the first year. Say 90% of the 95% quit on the first year since most people who get into this game can’t be stupid enough to keep going. (?? )
What of the remainder? Now they probably split into those that bobble along making enough or breaking even so that they keep trying. And maybe 3-4% start making good money.
So now, who are they getting it from? Surely:
Companies that are compelled to make trade payments or hedge exposures when currencies move adversely;
Banks that hedge their global fx risk (eg, if you earn 20% of shareholder returns in subsidiary A in uzbekhistan then you buy a forward against the expected earnings so that your EUR shareholder doesnt get mad - half the time you lose money on the hedge but that’s not the point for you)
Anyway, so structurally there are retail players doomed to fail and corporate players who know that half the time they will lose (but don’t care about that). Hence if you have a strategy that is unconstrained by the drivers that the ‘losers’ are constrained by, then you can wait until they are compelled to lose and hence you may gain.
Modern mystery - like the name btw - by this reckoning we can’t all trade the same strategy (the losers have their own strategies and can’t change). But also, some of us are destined to lose. All part of the learning process I guess!