Could profitable trading cease to exist?

[dbphoenix]

And how does one know he/she has learnt? Positive, consistent P&L, or is it more than that?

Nope, that's about it. But not over a few days or weeks or months but over years.

 

[stock777]

There are only 300,000 or so daytraders making a living, so even if they all go back to flipping burgers, its not big deal.

et can become a poker site.

 

[d08]

I know worriers and it's always futile; their worst fears rarely transpire. I agree with the sentiment of what you're saying: things will change, so be prepared. But you could flip "you'd be stupid not to worry" to "you'd be stupid to worry", and I don't mean that facetiously.
...

Absolutely. For me the first step is worry/uncertainty, that is followed by either looking for alternative methods or planning for life after trading. It's easy to get comfortable when things are good. Simply worrying without follow-through is an useless waste of energy but for some us, a function of our personalities.
I believe once you get comfortable, then "they" will get you. Even if I'm wrong, I can't afford to take a chance at this point.

 

[Aileron]

Why?

Why not build a win-win for every scenario?