Here is a nice article by Dan Woods in Forbes about the popular concept of crowdsourcing.
In some ways he is constructing and attacking a strawman ("crowds create innovation"). But the article does clarify that the real value comes from OpenSourcing -i.e., allowing pretty much anyone to attack a problem or come up with a solution. As Dan says, it is usually a few virtuosos- obsessed individuals-- from within the crowd that do most of the work.
The key is to ensure that you don't predetermine who is eligible to address a problem, or which types of expertise are the relevant ones. Creative solutions and breakthroughs often come from outside the orthodoxy, not within it.
Crowdsourcing does have a role when you need to get feedback on a concept from potential users to see if it is is marketable, or to take the temperature of a specific population around an issue. But that is different from coming up with the breakthrough ideas.
So what closed systems, organizations, and companies have to fear is not crowdsourcing. It's OpenSourcing.