Two big things. First, because the economics of modern pinball are brutal, venues mostly stopped buying, so manufacturers and their competition shrivelled up and with it, supply. The supply-side market at this point is effectively dominated by individuals and collectors, neither who want to part with their machines, as they’re nostalgic items and they know they have value.

Furthermore, working machines come at big premiums as repairs are finicky, expensive, and time consuming - god help you if you own a machine and some targets or rollovers on your machine give out, as it’s challenging to find someone who’s even capable of doing the repairs, let alone pay their price. The expertise to do it is really thin these days because all the people who historically used to make a living from it are all getting old and retiring. This combines with a second problem: although widespread 3D printing helped a little with making repairs more doable, parts are hard to come by and often demand cannibalizing other old or dead machines - meaning a working machine is worth its weight in gold, and so is a dead one: Either it has interested players, or it’s of value for salvage. This “literally every machine is valuable” situation drives prices up, even if the machine is essentially dead.

Lots of moving, mechanical parts, all handcrafted and hand-wired, machines built in small production runs (only a few thousand machines of a specific type usually) - there's just not too much room for the typical optimization approaches of "scaling production up" and "scaling things down to integrate more".

Though todays' manufacturers already try the latter, otherwise those machines would be even more expensive. You should take a peek into the belly of a machine when you get the chance somewhere - ideally into a newer machine, manufactured after 2010, and into a 90s machine. That's a stark comparison: the 90s models have thousands upon thousands of individual cables, wiring hundreds of individual lamps and solenoids and sensors. On the newer machines, manufacturers tried to cut down on the number of cables, pre-fabricating larger modules with LEDs on large PCBs, or installing sub-controllers from which solenoids are driven instead of wiring all of them individually with hundreds of large cables into the backbox.

But there are limits to this kind of optimization. After all, pinball machines are mechanical contraptions that need to integrate lots of individual mechanical parts spread over a large area. If you can't replace them with solid-state elements (which is basically what a virtual pinball table does, by replacing almost all mechanics with a screen) or concentrate them into smaller areas, you can only gain so much using modularization.

Besides the other replies, 9k is on the premium end of the spectrum - literally so, pinball machines come in trim levels like cars and 9k is the price for the Premium class.

There are Pro models for 7k new or typically 6k used, and also some Home models for 5k MSRP and often under 4k at street price. They have less stuff than the premiums, but you can get into a modern machine for way less than 9k.

Because they are still sources of income so you’re paying a premium. I did chuckle that none of the other responses mentioned this, but the new business model on them is to run them on location a couple of years and then resell it to a home collector for nearly what you paid.

It's what the market will bear. The particular machines you were looking at are sold on the collectible nature of these specific machines - new machines, limited quantities, licensed IP, etc. You get a guy who overlaps any amount of interest in pinball and something like jurassic park, and they "have to" have it. Then you get the people who see the price and think of it as a status symbol that they can show off along side (or maybe in lieu of) their fancy watch.

Used machines in perfect working order from back when there were arcades are way cheaper.

Probably because it's what the market will bear. It gets worse too, as maintenance on pinball machines is expensive: Labor intensive and time consuming.

They're complex and generally handmade. There's not too many of each type made and they rarely make more, so the price follows suit