Sure, you are spending what you earned. And if that is what you are doing, living a less expensive life so that you can finance your entire life with fewer working years, then that is perfectly fine. Probably even worth encouraging as this probably means you are consuming fewer resources.

2. If you take some of the wealth produced today, and instead of immediately consuming it, you "invest" it in something that enables more wealth produced tomorrow than otherwise would have been possible, you should be rewarded with some of that extra wealth produced.

3. Time value of money. Loaning your money or investing it carries a risk. If there is some chance that you may not get it all back, then there must be a premium charged to whomever wants to use your wealth today. Otherwise, you might as well spend it all as soon as you receive it.

In principle I agree, you should be compensated for deferred spending and incurred risk. But something must still be wrong as the outcome makes no sense. If I had to guess, I would maybe suggest systematic overcompensation, i.e. maybe the expected return should actually be exactly zero. But this is impossible to do and then there would be no incentives to invest, so the target becomes positive expected returns.

But as soon as the expected returns become positive you enter the territory of exponential growth which is not sustainable. At the very least returns should eventually drop to zero when the invested money has been multiplied so often that there is no more demand for investments. And all the time you are probably creating huge inequality and with this inequality one might also end up with a distribution of power where some can essentially demand further returns even if they should actually be zero.

In the end I have to admit that I can not truly point my finger to the issue, yes compensation for investments sounds reasonable if you discuss it on its own, but if you look at the consequences at large things do not match up. Your money does no actual work, it creates no value on its own, why should it still allow you to live without working?