Decided to think about Helpouts from Google's perspective. I don't see it as a stand-alone monetizable business, put into the market to compete with LiveNinja. Rather, it's a strategic move by Google to strengthen its ecosystem by:
1. Onboarding more people to G+. G+ is Google's attempt to create a single social identity for each person across all Google products, thus uniting what can seem like a fragmented Google experience. Having Helpouts (using Google Hangouts) is one way to drive new users for G+ through a specific use case.
2. Developing real-time results for help in Google Search. Imagine what will happen when a user searches "math tutoring today" - Google can offer real-time suggestions from Helpouts using Universal Search and Knowledge Graph.
3. Driving new business accounts on Google Apps & Google Analytics, plus sell more ads. When Google encourages skilled people to create Helpouts, they are basically increasing the number of enterprise customers they can potentially recruit for Apps, Analytics, and oh yeah - search / display ads.
And a random idea:
4. Using recorded Hangouts and posting them into a new category on Youtube. Could increase the overall quality of instruction. Also Youtube could be a great way to source Helpout teachers.
If Google chooses to achieve scale - by integrating with search most likely - it will be difficult for LiveNinja to compete on a broad scale. As previous posts mention, a niche / targeted approach may work better for LN to secure loyal users and deter drop off to Helpouts.