They would be here in a heartbeat if there was money to be made.
1. Visas. There is an application consul fee per country of nationality. Thus, five German members of Wu-Tang Reich pay a single fee to the German consul. With Avantasia...just off the top of my head...Sammett to Germany, Cately to England, Matos to Brazil, Lande to Sweden, etc, etc. Bands also eat the cost associated with traveling to a consul in order to complete their interviews. That's not going to happen here. If a person has to fly to the other side of the country, then airfare, etc has to be covered. And before you say, it's not that far to drive or get on the train...I had to pay for Nocturnal Rites to get to the consul because they evidently live in Bumfuck, Sweden. I can't see Jorn saying..."no problem...I'll take an extra day away from my day job."
2. Professionals- Hungry bands do shit to promote their bands. They are willing to gamble on expenses if that is what it takes to go from being Latuna Boil to Lacuna Coil in the States. As for Avantasia, nobody in the project gives a fuck other than Toby. They are not appearing live for publicity or to further the Avantasia name. They are getting *paid.* In most recent instances, it's more than what their normal bands are bringing in for their wallet (Magnum for example). They are getting guaranteed money, not a door cut or bonus. If they don't get paid, then laryngitis suddenly appears.
3. Draw- Avantasia draws 5,000+ down South. They would be lucky to get 500+ in Chicago on a weekend.
4. Logistics- The performers do not get in the van so to speak. They are not going to live on a tour bus together. They don't split a room at Motel Six. You are looking at 20+ hotel rooms alone for a single night. Don't forget the logistics in getting from the airport to the club if you fly them in like they do in SA. That's an extra $500 easy here in the States just to cart their ass 15 miles.
5. Food- Bands go to White Castle or Waffle House to eat. These folks are given a per diem to eat 3 real meals/day or chow down at the royal buffet provided for them. For shits & grins, give them $100/day each.
6. Ego- You are headlining Wacken with a HUGE production. I can't see Tobias going, "well...it wouldn't be that bad to play at a shithole like the Masquerade. Hey Kiske..."
I'd guess that Milton was rather close in his estimate of what it would take to make it work here per show. I didn't even bother to drill it down to a actual number for the fest once they started throwing logistics at me to make it work.