I think trading is one of the best methods to make money from bitcoin and altcoins. But it is not so easy, you need some knowledge about it, otherwise it is so risky. You can participate also in the Bounty campaigns and earn some tokens for free.
Most people will lose money trading. I lost quite a lot at first (both coins and dollars). Over time, I became a more consistently profitable trader, but it took a lot of patience and hard work. You need to be really patient holding altcoin bags. They are really illiquid and you can lose a lot of value instantly. It's important to learn how to patiently hold through such market action.
It's not only in crypto. In the stock market most traders lose money too, at least that's what the statistics say. I think the best way to profit is holding. But it might be a good solution to use part of your portfolio to trade, if you really want to trade, and the other one investing and holding.
Yeah, the 80/20 rule generally applies to all forms of trading (and more broadly, to most statistical distributions). As with cryptocurrencies, the best way to profit from the stock market is holding as well (considering the ongoing long term bull market and stiff capital gains taxes).
Some people definitely have what it takes, though. As was mentioned, the most important aspect of trading is risk management. And managing risk properly means controlling your emotions and handling losses in stride. That's where most people fail IMO.