I don't think any game can hit those numbers anymore. 20k.. So , as a comparison.. There are 33k user accounts on pinside. Say the pinball community as a whole is triple the size of pinsiders, maybe that's low but nobody knows. So 90k total people that are interested enough that might buy a pinball machine.
So to hit 20k... 1 in 5 of all of us would have to buy it. This in a market when 5 manufacturers are shipping, the games are expensive, and Stern will move on to the next game in a matter of months which will move the buzz on to that, and begin at least some 2nd hand market.