The biggest problem is they needed to be the "Backend" here. If they just got a cut of the 30% LSAT/SAT sites and those sites simplified their stack it would be a win all around. Look at AirPair, Their core product was their network using hipchat and Hangouts to accomplish the goal. If sites could leverage this technology (read: google marketed it as such, a technology, not and end product) I'd suspect some of those sites would have leveraged it.
I put it on my site, but no one used it. It was on the sidebar of every page. People just clicked on the "tutoring" page instead.
I'm not sure it would have worked for LSAT/SAT at all. People seem to want to talk to a human before they book a lesson, since they're expensive.
In theory, people could find it very useful to consult an expert for five minutes. But in practice the sort of people who would want to do that don't even look for a tutor. The typical tutoring students wants hours. If the client is a parent, then they're looking to hand off the problem to an expert. (For almost all SAT tutoring, the client is a parent.)
Could you see this working outside of a technical niche?
People have specific places they go to look for LSAT tutors, and google helpouts wasn't one of them.
LSAT is more specific than some other niches, but I imagine this same problem occurred in most areas.