We only have ourselves to blame for high pinball prices. We as collectors set the market prices with our pocketbooks. As long as the demand is there and people are willing to shell out $7K or more on a pin the prices will continue to rise. At some point though the market will be saturated with these high end collector machines and prices will have to come back down. We only have so much space and cash that we can allocate to pinball.
My guess is that once JJP is producing games and they are able to keep up with demand that Stern will drop prices into the $5K range again to pickup the lower spectrum of the collector's market .-similar to what Data East and Sega did in the 90's. I don't think there is room for two manufacturers in the $7K and up market. This may not happen for another year or two (maybe on JJP's 2nd pin?), but I think it will happen. Right now Stern is just taking advantage of being the "Only real maker of pinball machines", but once it has competition I think they will have to adjust their business strategy to remain successful.