Most of us are players first and collectors second. So yeah, if a brand new MMR plays just as good or better than a routed one from 20+ years ago, Hell yeah I want one!

Bubbles usually require a catalyst to burst. I know that because pinball prices stayed the same or increased during the last recession that people think its a recession-proof hobby, but I would disagree.

The hobby has expanded with many many new collectors, which is great! That expansion coincided with the last recession, which kept the prices afloat. I think the timing of the new collectors entering the hobby was mostly coincidence. But not all collectors have the same financial profile. There's people with large net worths who get every LE. And then there's people buying games on the margins with bonus money or a small stock market win or something.

I believe we're overdue for another business cycle contraction/recession. When that happen the wealthiest will still buy games. But the collectors who need to raise money due to a job loss or business slowdown will not be buying and probably be selling. The decreased demand combined with the expanded supply of new games and new manufacturers will lead to lower prices. Because the total collector count is still well above what it would be 10 or 15 years ago prices won't go back to the 'good old days' that I missed out on. But I think we'll see a correction in prices. If I had to put a value on it I would say 30%. That's what the housing market fell. I conflate the two because pinball and houses are both illiquid and require time and effort to sell, unlike stocks.

Other factors
I also wonder whether pinball as a hobby could be a trend or 'fad' for some. Will the new collectors who entered the hobby 5 years ago or less be collectors for life?
Pinball prices are regional in some sense since its reasonably a pain to ship a game. and most games do not change hands on eBay so prices paid are opaque. Will a price decline hit some areas first? Since I think the next recession will come out of California and the second tech bubble, I would imagine it might be harder to move games there and could be the start of the price decrease. (Also helps that this is where the games are most expensive in the US anyways).

I disagree. While it's true Europeans and others get a great deal on healthcare and college, they overall do not have the same materialism or wealth as the middle class in the US. They spend a ton on housing which is usually NOT single family and condusive to pinball ownership. My English friends live in small flats and mostly spend their money on travel and experiences, not giant toys. If they are into toys it's usually motorsports like cars or motorcycles.