Quoted from Rando:

Depends on what your definition of "big" is.

Some population stats for comparison:
Top 10 Most Populous Countries
Rank. Country Population Rank. Country. Population NaN
1. China 1,349,585,838 6. Pakistan 193,238,868
2. India 1,220,800,359 7. Nigeria 174,507,539
3. United States 316,668,567 8. Bangladesh 163,654,860
4. Indonesia 251,160,124 9. Russia 142,500,482
5. Brazil 201,009,622 10. Japan 127,253,075
Ford sold 83,000 Mustangs last year, that's .03% (I think? My math is awful) of the US pop buying a Mustang last year.
Ford made their 1,000,000th Mustang in April of 2013. If say 50% of those were still running/owned, that would be .16% of the US population if each person owned one.
I imagine that the number of Mustang owners is higher than Pinball owners. Although .1% of the entire US population is pretty big as a size, it's still pretty rare that you're going to come across another one in the wild.
Right?

Quoted from Rando:

I disagree with that statement, which is why I chose a Mustang over something like an Accord. Some of the newer owners are just car drivers yes, but I would consider any Mustang still around with a production year of 64.5 through say... 2005ish to be owned by a car enthusiest, that likely owns another vehicle as their primary transportation, and I would classify as a Hobbiest. And Mustang owners don't define that Hobby, they share the hobby with owners of old Camaros, Chargers, 'Cudas, and many other old cars that don't start with C. Including myself, I know 6 or 7 people "into" cars enough to own a rare/unique one.
I'm not bashing Pinball as a hobby, it's awesome, I'm just saying that it's a really tiny one. Ranking it among other Hobbies based strictly on size, I'm guessing we're below Car clubs, motorcycling, coin collecting, etc. Maybe on par with people who fly small planes? That may even be too big, I personally know 4 people off the top of my head who do that... Just a guess.
Now I do know a bunch of people who would LIKE a pinball machine, but none enough to actually actually pull the trigger on one.