I don't overlook it - I acknowledge that it needed a billion to get off the ground. But your point was that removing Levy and Lewis would make no difference to how we're run - the same can be said of Mansour at City now. The billion it took to get there is a fact, as is the fact that said billion won them two Prem titles and a smattering of cups in eight years, versus our paltry investments winning us one League Cup in sixteen years.
As for the Mansour/Etihad connection, it's more complicated than that. What was once well above market value is now no longer that far-fetched - and Etihad is run by some very smart people unconnected with Mansour who share that view. The City deal is a sponsorship that covers the shirt, the stadium and the training ground and is worth about 80m a year (iirc) - a comparable amount to what Chelsea or United would get if they packaged their sponsorship deals like City have done. United actually might get a lot more if they offered a shirt + training ground + Old Trafford sponsorship deal - judging by the size of the Chevrolet sponsorship alone.
There is no evidence to suggest now that Etihad are paying above market value. And the same goes for executive boxes.
In short, you take Mansour out now, and it's unlikely there would be a radical change anywhere at the club, I think. As for their ground, it's a formality - there are few alternate uses for the place, and by pressing for expansions to the stadium funded entirely by the club, City are de-facto buying it out over the medium-term anyway. The 250-year lease they're on suits them perfectly, but it can be changed to outright ownership for a fairly minimal fee, I suspect.