We have some of the most intelligent people in the world working on extracting as much wealth as possible from high volume trading. For someone to gain money in the market someone most lose. Imagine if we had these minds working on solving real world problems that would actually benefit society. Just like gambling, trading is zero sum.
You're right about that, except the loss is often intangible losses. For example someone selling before the price goes up will think they lost out but really they didn't.
There are enough great minds to go around that high volume trading can be spared a few. Most people who are at the top of this field probably aren't that capable of transitioning in to solving the issues you're talking about. Being intelligent doesn't mean you're capable of doing just anything, you have to have something that drives you.