we only really “need” investors because of the structure of our economic system. we need humans to do stuff regardless of the system.

worth mentioning that our current system is setup by and for the people who own the stuff so its no surprise that we need them to make new stuff.

Using your own logic, if we need investors to make the whole thing work, then an investor playing their role has obviously earned their take. If they didn't exist, many things would simply never have been created.