Usually, us Aussies are a few years behind with the "pinball trends", but over the last 5 years, our market has been completely saturated and demand SHOULD have slowed down. But it is not. A scan of eBay Australia is not an indication of where the market lies, as it is full of overpriced and under done machines. Projects at 5 times their values, and "rare" games ("rare as in "Raven Rare")..
It is simply a global trend. Pinball has been "back" for 2-5 years, and the demand is increasing. Therefore, the market prices are high (but not to the over inflated prices on eBay). But like all trends, it has cycles. Once demand drops, or the market is over supplied, prices will change as suppliers struggle to move stock. You just need to look at the inventories of dealers to see the high priced games are not moving. We may be close to the tipping point.
I'd say you will find the games you are after, but not on eBay or CL. Both are used as advertising to find the newbies that have not done their homework. Have you tried Mr Pinball Classifieds ?