Nobody said it was going to be easy; if it were easy then everyone would be doing it. Wait - everyone is! But not everyone can do it well.
If people come to your site and have no reason to come back, that's not a failure of Google to deliver traffic (sorry), that's a failure of YOUR business model. Or a failure of focus, if your site isn't a business. As hard as we all work to get traffic, why the heck wouldn't we want to figure out a way to KEEP that traffic?
If you create a plan or a site or a business that depends on someone else sending you free traffic, your users coming once and then never having a reason to bookmark you or come back, well then, you got 99 problems and none of them are Google.
Don't get me wrong, you can make your site as much or as little as you want. But if you're only willing to go so far in what you offer, then your expectations should only go so far as to what you'll get out of it.