I can't say what kind of deal they made for a tour like this, but usually bands like Opeth don't really make much money doing a tour like this one. So much of the money made goes back into tour expenses and whatnot. They likely made enough money to send back home to pay bills and stuff, perhaps a little extra, but thats about it.....
Put it to you this way, I know a band who are on a bigger label, have toured the past 15 months or so, have videos on mtv and all that rubbish, and play to lots of people at every show.....and they still dont make enough money from it to be able to live on their own or buy a decent car, because they technically still owe the label for the costs of recording, touring, etc.....
Like I said, Opeth probably make just enough money to be able to live and get by. But I don't think they are remotely close to raking in the dough....and as for success and fortune changing people, that is true that it does happen. But honestly, Opeth are pretty sincere mature guys and I dont see that happening to them...and unfortunately, I dont see the likelihood of them ever becoming that rich and famous at this. Though I think they fucking deserve to be! \m/