This is a very long youtube, over one hour, but I did listen to most of it, at least up to the questions at the end. Although Adam Grimes does appear to wander in, out, and around, the topics being discussed, there were some interesting points being made.
I was pleased that although the title describes forex trading as "challenging", in the actual video they use the more realistic terms "hard" and "difficult"

His answer to the question was actually refreshingly different to the usual reasons why traders fail. Normally failure is put down to the traders' own mistakes, such as a lack of experience, or training, or discipline, or patience, or adequate funding, etc ,etc.
But he identifies the cause of difficulty in trading as being a characteristic of the market itself, in particular its randomness, which he claims is present in all timeframes including longer time timeframes like weekly. And he describes the edge in any trading method as being extremely small.
However, what I found very revealing was that he didn't say that markets are random all the time. He says that they are random
for much of the time and that there are times when one can expect randomness to be very much less present. In particular, he uses the example of when markets have moved to the outside of the extremes of normal movement and are not likely to remain there - I kind of think of this as contradictory trading and is something that I have been exploring myself a little in connection with S/R horizontals and which ones are most likely to hold.
Whilst I am a doubter of the randomness theories in general, I do accept that, as the speaker says, there are very many different reasons and size and timings why people enter the market when they do. And because the market is huge and free moving, its reaction to all these inputs will appear on our screens as the familiar ups and downs, spikes, and reversals. But I believe that within the apparent randomness there is an identifiable core baseline that provides us with a reliable edge. And that only leaves us:
a) the concrete issues of when to enter and when to exit
b) the behavioural issues of patience and discipline
c) the financial issues of controlling R:R and protecting our account equity
Just my thoughts on it