As to your question about how they recoup the 11-12 billion they 'spent'. Well yes that's 11-12 billion down the drain, but now they fully own a streaming service, twice the size of Hulu, for basically 1/6th the fair market value they are about to pay out for the remaining portion of Hulu.
Additionally, Disney will wind up with all of Hulu's profit, and not just 66% of it. The profit from Hulu will jump by 50% (going from 2/3 to 3/3).
And then if Hulu is subsumed into D+, well, then Hulu's profit is D+'s profit.
D+'s success has been slightly suppressed by Disney sending a lot of the new content they create to Hulu instead of D+. Imagine if all those successful Hulu shows were on D+. Well, they soon will be.