You mentioned people "with money" that can maybe afford to throw a little cash at things like this, but for small guys like the majority here, they need to seriously get involved and not just throw money at something.
Even someone with no knowledge of the stock market doesn't just call some stock broker up and say "Here you go, Joe. Make me some money." I monitor every investment I have and also speak with the broker as to why or why not we should go ahead with something or pull back.
I own 2 duplexes within 30 minutes of where I live. I don't pay a property manager to do anything. I spend less than 10 minutes a month with each tenant, and that is typically when I collect rent. And of that, I'd say that 9 of the 10 minutes is spent shooting the shit with them afterwards. If something small breaks (plumbing, etc) I take care of it myself. Why pay a plumber $75 to come out when I can take 30 minutes of my day or less and fix the problem for $4? If it's something I can't fix, I call someone who knows how to do it. I have a wife and 3 children yet still manage to be able to pick up the phone rather than pay some scum realtor/manager to call for me. The only time I would ever consider paying a manager is if I didn't live in the same area. Obviously, with an apartment complex, one would need hired help, but I would still be 100% sure of what was going on at all times. Owning property can be extremely passive if you are willing to put in a little work. Both of my duplexes were remodeled and tiled by yours truly. Yeah, it took a lot of my evenings and early mornings and weekends, but I was getting my income "passively" much sooner than if I had just thrown some money at people and said "fix it and rent it." The $20,000 and elbow grease I put into them would yet to have yielded profit if I had paid for everything to be done.
So yes. Your obvious recipe of 1 part cash to 1 part knowledge works to an extent that one can synergize and be the money half while someone else does the brute, but it's not that easy and 9 times out of 10 ends badly. I said nothing of having to "work hard" on every new venture someone starts, but any investment that someone just throws money at expecting an easy return is probably about as good an idea as a left handed football. Nothing comes easy and a guy has to be an idiot to think he can make long term income on something he is unwilling to at least learn the ropes of at first.