They don't even get their legal costs back most of the time.
"Financial penalties are a legitimate tool to achieve compliance when used judiciously. Logically, if the only penalty for violation is simply compliance with the original rules, bad actors will just wait for an enforcement action before even reading the GPL. That social model for copyleft and its enforcement is untenable and unsustainable. An enforcement system without a financial penalty favors bad actors over good ones, since the latter bear the minimal (but non-trivial) staffing cost of compliant distribution while the former avoid it. Copyright holders (or their designated agent) therefore are reasonable to request compensation for the cost of their time providing the compliance education that accompanies any constructive enforcement action. Nevertheless, pursuing damages to the full extent allowed by copyright law is usually unnecessary, and can in some cases work against the purpose of copyleft."
Based on their 990 forms that they've submitted to the IRS in 2011-2013, they are averaging $100,000/year in settlements. Which is pretty impressive considering that they don't develop software.
I do realize that they have other sources of income, via donations and conference services and what not. But that doesn't change the fact that their legal activities bring them revenue.
I see it as the Software Conservancy spitting some reality into Linus' Cheerios. But then again, I've been forced to replace devices because Qualcomm/Mediatek/Obi/D-Link decided GPL compliance wasn't their cup of tea. So I'm probably biased.