From the part of my post that you edited out, was there no "good" attached to the condition of the trader? Now, if the situation becomes equal where the trader is good and the investor is also good at their jobs, won't what I said subsist? That's just it unless you do not want to accept the fact. You only brought this up from the judgemental of how trading is difficult to profit you (because people lack the needed psychology and expertise) and investment is easier to profit you without regarding the general possibility of how the two can profit you if you are good at them both.
Holder being good means that he just holds and doesn't sell, so there is a quite limited amount of profit they could make on the long run, there isn't really anything more they could do. You buy, you hold, that's all the holder can do.
A "good" holder would just mean that it would be someone who doesn't sell when the price goes down but just buys more to make sure he does DCA, nothing more, that's all a holder could do, hence why it's limited and can't be all that different.
Whereas, a trader isn't someone like that, a trader could lose 100% of their money and be broke, or he could just trade and make 100x return too, you can't make that kind of return holding, maybe some alltcoins if you are lucky but not with bitcoin, or any other investment like gold or properties as well
Hence, a trader could make a lot more than what a holder could make, if the trader is a good one then there is in theory nothing that stops them from making an unlimited amount of money, going from just 100 dollars to 1 million dollars isn't impossible for a trader, especially with how the high leverage trading works. This is the difference, nobody says trading is better, we are just pointing out a good trader will make more than a good holder, but most people are not good traders in real market (compared to their theoretical knowledge).