Because not all are here to listen and follow good advice. Some just forget about it and continue doing what they think is right.
In fact, we have to be thankful to those old traders for sharing how they stepped out of their mistakes for us to change. Unfortunately, instead of doing what they say, we do the opposite and commit the same mistakes that the old traders did before. I could say that no matter how much advice we give, nothing happens if we don't see it as valuable. We are still doing wrong before we learn something.
It is better to learn through the mistake of others, than to have a bad experience. I suspect that the reapn why some trader don't take advice from experience ones is because of greed. They want to make quick money from trading, so they end up taking uncalculated risks that can lead to big losses. Some of them end up learning their lesson the hard way when they suffer losses. I am not an active trader because I have not gained enough knowledge to start my trading adventure.
It's true, because prevention is always better than cure. Learning doesn't always have to come from one's own experience. There are many other people's experiences that we can learn from. I also agree with you that one of the reasons why traders, especially beginners, often find it difficult to accept advice from others is because of greed. Furthermore, they often have a selfish and arrogant nature, thinking they can do something right to achieve large profits when in fact they are trading with the wrong approach.
For me, trading is an activity that takes a lot of energy and time to learn. There are many things that must be considered in detail, such as when the right time to enter and when the right time to exit. Many beginners enter at the wrong moment, which actually results in significant losses instead of profits. Greed, laziness, arrogance, and selfishness are often difficult to overcome in traders, especially beginners.