It seems to me that if the project is really promising, then it will find his investor. About their projects, all developers say that they are good and promising. This is not always the case.
Now such a huge competition among projects, that without large investments in advertising, the investor simply will not be able to find out about a good project.
Yes you are right. If you reason strictly mathematically, most of the money is spent inefficiently. I mean money for advertising. Since now advertising carries a function not to convey information but to "shout over" the advertisement of a competitor.