depends on what you call "chop" or "trend" and it is all relative to the time frame you are talking about. I can't remember a forex pair that didn't at some point trend on an 15 min one day chart.
Most traders fail because they trade on smaller time frames. If traders trade on higher time frames with good money management then losing traders will become very less.
Most of the trader believe in the saying that, they can earn from the market very easily nad in greed they just jump in to trade without any planning and ending up losing.
Have you ever asked yourself why most successful traders either: 1) Trade OPM 2) Come from the Northshore of Chicago? It is because the biggest impediment to making money in the markets is when you have to make money to fulfill some need. That need is usually economic, but it can also be a need to gamble etc. When you meet either of the two conditions above, you have taking your own money out of the equation, and the psychology is correct to learn the trade. The biggest reason retail traders lose is because trading has to be about winning more than you lose. That the score is kept in currency, that blows up most people psychology. But what if the score was kept in rocks. What then? Therefore, trade size so small that the money won or lost is completely irrelevant. Use this time to develop tremendous habits. Then when you get your real chance, your skills be they market skills or discipline skills or psychological skills will all be lined up. So, retail traders lose because they jump at the deep and of the pool when they should be in the shallow end for at least three years. Probably longer.
I'd say "impulsive trading". For any trader : compare the results with all the trades, compare without the impulsive trades. Again : psychology/spirituality.
getting to the heart of the matter, most forex traders fail because they have no edge and this is primarily because they do not understand the participants they are competing with. It is not suitable for beginners even though it is marketed to beginners. The situation they find themselves in is akin to entering a poker tournament as a novice where you are short stacked and everyone else is a pro. I cant tell you where I got these 2 graphs from, they are charts of net dealer inventory throughout the week. Of course dealers (banks) make money from 'flow' but that is not their only source of income. note - dealers like to go home flat, check the graphs. GL. for the informed, yeah the volume is light in millions. They are from the 90s DEMUSD.
I doubt FX is much different to anything else. It's just that the banks/commercial traders etc have an 'edge' and we don't as they have info not available to us retail guys.
Dealer Inventory half-life is measured in minutes for FX, in stocks it might be days. Yes the larger banks have the edge of seeing flow. Of course there is no low hanging fruit but FX is a bad place to start imo.
Here is an interesting article: Six in Ten Mom-and-Pop Currency Traders Lose Money Each Quarter http://blogs.wsj.com/moneybeat/2015/01/16/six-in-ten-retail-forex-traders-lose-money-each-quarter/ According to the article, 99% of small traders lose annual. The article also points out profitable traders open an account with a firm that have an extreme higher minimum deposit requirement, while small traders open an account with a firm that have an extreme lower minimum deposit requirement. In other word, poor people shop at walmart, while rich people shop at wholefood poor = losers This is not only fx, but to futures, options, and stocks More than 90% of small traders lose! They just lose!
I am sure everyone here would agree that the majority of traders lose across all asset classes. I think what the OP was asking was the reason WHY. My opinion is they are trading without an edge and they don't have an edge because they don't know how to develop one with the poor understanding they have of the other participants.