EDIT: Holy crap, everyone. Please refer to my two responses just below about the reason I said "Ideally." This statement is in response to "what possible ways are there to guarantee it other than a meaningful amount of regulation." So I gave one.
I'm sorry but the idea that the market will solve every problem the world could ever dream of is a ridiculously out-of-touch-with-reality idea. Though the idea that Congress can come up with laws to solve even one problem without creating side-effects is equally naive.
The 'market' can be gamed, and there are plenty of people that make a career out of it. As long as you can bury the truth in bureaucratic nonsense and hide behind diffusion of responsibility you can get away with practically anything.
"Ideally, grapefruit would just take care of it."
But there's a reason for the first word of my statement.
There's a whole set of well-defined problems in which everyone following their individual interests, the "invisible hand" so to speak, lead to a clearly terrible situation -- monopolies, prisoners dilemmas (collusion), tragedy of the commons (pollution, resource extraction, public education)..
Talking about how "ideally the market would take care of those problem" is just silly, the market will categorically not care about those problems -- it's not an intelligent force, just a sum of individual actions.
I hate my health insurance company, cable company and cell phone company -- what are my options here in this supposedly free market, start my own multi billion dollar nation-spanning infrastructure?
So, to say that "the market" will take care of something is equivalent to saying that a set of human beings interacting with each other freely, voluntarily, and without coercion will take care of it.