I personally think the main reason why bounty hunting is not as profitable as it used to be because of the market conditions which is making it hard for ICOs and projects to raise money for their project. Trading is a really different thing and it is not every body that have the knowledge of trading which is why most people are still participating in bounties.
That is what is easy to do now is to participate in the bounty. As you say that trading cannot be done immediately by everyone when they first do it. So now what is done may be a bounty. I also do that now to the future. But someday maybe you will enter the world of commerce, want to try something new.