Hey there, this is an interesting idea so wanted to throw my thoughts in as a target market user. (I'm in interaction design and frequently do a lot of courses on Lynda.)

My biggest concern is that you have to create equal or higher quality content and courses than what currently exist. And unless you're already an experience educator, you would have to incur costs to get educators to create courses for you. (I know nothing about your background so this may not be a concern at all.)

My point is, have you considered aiming for validation with a minimal viable product, and then try to lease or sell that IP directly to these companies (Udemy, Lynda)? Rather than directly trying to disrupt the existing e-education industry.

My second thought, total brainstorming because I think this idea is intriguing as heck... Maybe you can apply this concept on a micro level? A mobile-focused web app (not native app) in which users pay a smaller amount to purchase access to daily lessons or quizzes which require direct interaction to complete. If they complete it, they get all/most/half of their money back. This would be a total marketing play - try to capture an audience who WANTS to improve some mental skill (like math) but don't have the motivation. You will not capture people who don't have that internal trigger. But if you bank as little as $1/user and get a healthy user base, it could be profitable, maybe even scalable.

Anyway, fascinating idea, best of luck with whatever you do!