Looking at the math and what he accomplished on his last big tour in the 90's (with over 5 million people paying to see him), it's certainly probable. Got to love all the methods that he and his crew are using to battle scalpers, mostly by having just enough shows to always meet demand without having too many empty seats over the last few nights.
Obviously, U2 is a bigger draw in most areas of the world and didn't even come close to satisfying demand for 360 given how quickly a lot of nights sold out. I'd expect their upcoming North American arena shows to sell out in five minutes flat. For example, two nights in Oakland's arena would mean playing to only about half the people (at most) that they played to in one night at Oakland's stadium. Therefore, demand for the arena shows will be at least double that of the stadium shows since there's only half as many tickets to go around (and even fewer given that many, many fans will buy tickets for both arena nights - shutting out even more of the casual audience). It's gonna be mayhem.
