I saw a veteran of coin-op reflect how a lot of coin-op stuff outside of pinball is on the decline.
Woodrails have been diminishing over the last few years it seems.

My local impression is that all EMs are waning. Where people would snap up fun $700 EMs for the garage they are lingering longer and longer. I don't expect to see EMs rise again, outside of the most collectible (rarest, and top restorations)

A generation of people grew up next to woodrail pinballs and might have wanted them with that sense of nostalgia. That generation is mostly retired, downsizing, moving in to care homes, etc.
There are many of us that love the woodrails, but not enough to sustain the market at past (modest) numbers.

1970s EMs will have that same reckoning. 70s EMs are now all 40-50 years old, so the people that remember them from their teenage years are 55-65 years old, so that nostalgia period will be sunsetting as well.

There's not really anyone that remembers the 1930s from their youth, so the market for THOSE machines is just pure collectors, the nostalgia wave of that period long resigned to history.

I often think of the plummet of Elvis records https://www.theguardian.com/music/shortcuts/2017/may/07/elvis-presley-memorabilia-plummeting-in-price
I imagine The Beatles market is beginning the same decline.
Heck we're already past the peak of the Nintendo Entertainment System collecting, as 80s kids who wanted every cart grew up, got money,and went out and GOT every cart, but now some of them are beginning to downsize.

I wonder if in 2050 the kids of today will have any nostalgia for the modern ticket redemption arcades?

The tournament pinball aspect plays a role. Single player games just aren't that great in tournaments. Lacks the drama of competing ball-to-ball