the modern world does this, making money with money, if we had the money then to develop it into a more convenient than have skill because it must be depends from work.
It's not the modern world, there are still people who loves to play safe and only few of the entire population who are wiling to take bigger risk.
You make money from money if you are an investor and that means you are taking risk, the bigger the risk the bigger the reward.
By simply holding our bitcoins, that is already an act of investment and we all hope the value will increase so our money will grow and we can make profit.
That is how rich people do it making their money work for them. I don't know any more efficient way than to do it. Of course there is no guarantee that you will earn money instantly it requires careful planning and a steady observation of your business because you will never know when there will be a hindrance in the system. Also your earnings does not always depend on how much capital you have.