Speculate to accumulate.
Why not have a crack at the venture. We all sit here and say no, but let me tell you, that if there were a pinball arcade somewhere I and most of the other freaks here would pay a visit in a heart beat to support and also to help advertise by word of mouth!
Pinball and ice cream sounds - AWESOME (or similar gimmick) 
We all say and wish that pinball had a public resurgence, well now is the time.
Owners of business I know are always looking for a team building venue too, and show great interest in my pinball. LOCK IN SESSIONS!
Tell your mate GO FOR IT!
just don't plan on early retirement