Trading is probably the most efficient way to earn bitcoins, but you have to have some already so that it's worth it.
And you have to accept the risk that goes with it.
This way a living even in the richer countries should be possible.
Trading is not a good way to earn money for most people due to the trading cost involved. Most people will lose money.
I dont think so, most people will lose on trading if they do not have any knowledge on how to trade. But of course not all expert traders are in profit, sometime they lose as well because it trading involve risks like in gambling.