Even if they did "only" play to 46,000 in Philly a second night, I'd think that would still be quite profitable. The first show, which sold 70,000-ish tickets, would've paid all the "bills" for the event, and the 2nd show would pretty much be gravy on top of that (minus operating costs of that particular show). Remember, they deamed the 2nd show in Brisbane worthy of playing, despite only having around 30,000 tickets sold.
I admit, some of the American markets I mentioned are a stretch for a large 360 stadium concert... but so are places like Norman OK and Charlottesville VA, so whose to say?
As far as Ohio, I think Cleveland is probably too close to Pittsburgh and East Lansing/Detroit. In Columbus you have the OSU football stadium, which holds over 100,000 people (U2 played to 43,000 there in 1997). Cincinnati has a pretty small NFL football stadium, and it's within driving distance from Indianapolis (2 hours), Louisville (1.5 hours), Lexington (1.5 hours), Dayton (1 hour), Columbus (2 hours), and all points between. I think this could've been done.
As far as places that don't have "adequate" stadiums, if there's a will there's a way. See Montreal and Moncton, where U2 basically had their own stadiums built particularly for their concerts. And that stadium they played in Denmark was TINY TINY TINY, but they made it work anyway.