Predictions, hmm...
In ten years all of the Bally/WMS are held either by OLD people who got them cheap, or very rich people, or people who have very small collections. Pretty much what is happening right now, just accelerated.
All boutiques die in a big recession, Stern survives by shifting all material sourcing and manufacturing to China, or Vietnam, making VE or rebadged old pins, to order, for rich people. Stern systematically stops producing all replacement parts for all of their older machines, forcing people to buy super duper galactic limited editions from a select catalog for $50k apiece.
Similarly, Planetary remakes any machine controlled by their IP, to order for similar price, stops support of repair parts for older machines to avoid competing with itself.
As for the cargument...
The cargument, unfortunately begins to apply when the price of a pin and a car become more or less the same. Yes, it's apples to oranges, but both still both fruit, we are not comparing apples to steak. If pins were significantly cheaper, I think there would be fewer references to cars. It's the price which brings out all of the negativity. We have reached the point where everybody subconsciously knows they are being ripped off, just like when we have to buy jewelry for our spouses. We still buy, but know we are getting shafted, and it hurts.
The cargument really should not apply, comparing a 4000 pound high tech product which costs tens of millions to develop, to a low quality woodish box full of minimalized wiring, cheap LEDs, and a handful of plastic toys all based on manipulation of prior IP. There are hundreds of pinball machines worth of stuff in a car. But the prices are similar, hence the comparison. I'm not defending the cargument, just my thought on why it keeps getting applied.
In 25-30 years, the housegument will apply, and in some areas like within Detroit city limits, it already does. Lets see, a new Stern, or a big house? In 30 years you could sleep under a pinball machine if you have to, but the house might be a better bargain.
I hope that beyond 10 years, 3D printers and similar maker-tech can be used to effectively replace all unobtainium parts. Then even if all the manufacturers die off, people will be able to repair their games and maybe build entire games from scratch. I know lots of young engineers who design and build their own PCBs, hack everything related to code, and play with Makerbots. If the Millenials really want to play pinball without paying collector prices, they will eventually build their own.