There's this question that doesn't let me sleep at night...
From what I hear, investing surplus money is always considered a good idea because it lets your money "work for you" and earn you more money, even while you do nothing (well, assuming you've made a thoughtful investment and don't just lose your money).
There are various ways to do this, but at the end of the day they are just a variation of the same theme: you buy some object O for X money and then rent it out to people for Y money per month (or week or year or whatever). Y is a fraction of X, but over time it amounts to way, way more than X. X can be anything from cars and boats to real estate and even money itself (aka lending). Companies are a special case of this where the owner rents the company to their employees. The rules are twisted here to be in favor of the employees (instead of a fixed Y they pay whatever surplus they produce; and if they don't produce a surplus then the owner has to pay THEM), but if a company is making a profit, that's essentially what happens anyway.
And the great deal about it is that you, the owner of the object, don't need to lift a single finger. You don't put in ANY work at all, you just rake in the cash. And then with the new cash you can then buy more O's and make money even faster and so on until infinity. Wealth this way expands exponentially, or at least it does until some real life misfortune happens to slow it down for a while.
But here's the problem with this that I cannot get over:
This means that the "owners" are like vacuums for money. There's a fixed amount of money in the system and they just keep getting more and more of it. Eventually, if nothing is done about it, you should end up with a few elite owners that own ALL the money, and vast masses of people who own absolutely nothing, because they've had to spend their last dollars to pay their rent payments.
The government can, of course, print more money, but that leads to inflation and we don't do that much anyway. You can tax the rich people and give a part of their income back to the poor, but that just slows things down.
So... why are capitalist economies thriving and average non-investing people keep getting better lives (and more purchasing power), when theoretically the opposite should happen?