This is just a guess of course but I think a vast majority of pinball buyers are not made using a loan / credit card to purchase games. I could be wrong as many distributors now accept a credit card and apply a fee to the total cost. I would say 90% of buyers pay in cash / immediately pay off their credit cards while the other 10% are on credit / personal loans.
As for the $12,000 high speed game that's just unrealistic crazy Ebay pricing and it has been going on for 10+ years. The same thing occurs on Ebay with other collectible items.