There's often just a few family members or researchers that do all the research. The problem is potential relatives aren't going to get, or at least pay for, a DNA test unless they themselves are interested.
I'd suggest adding a button on each profile to gift a DNA test. Ideally, it'll give you the ability to choose a group i.e. male or female descendants of X. Once authorized, those profiles will get an email informing them that a potential family member has gifted X number of tests - 1st come 1st served. Their profile will also have a button added saying "claim free DNA test." That might help increase the amount of tests done and data on the website.