Quoted from PinballHelp:

Not necessarily. There are threads indicating there's new people collecting games, but there are also collectors getting out of the business, dying, passing on games, etc.
For example, let's look at Boston Pinball's ebay sales figure history for pinball machines:

We are seeing an increase in pinball sale prices, BUT we are also seeing a decrease in the amount of games sold.
So what the above graph can illustrate is not that the collector market is necessarily growing, but that the law of supply and demand works the way one would expect.
Another thing the above graph distorts is the "average sale price" which is undoubtedly going up because modern games are selling for five to ten times more than older games. So while it looks like "pin prices are skyrocketing" they really aren't. Their *Average price* is because now people are buying and selling $7000+ games in addition to the standard $500 EMs and $1000 SSs. When you take that into account, it doesn't look like the market is growing that much - there's just higher-priced machines being sold which makes the average go up.
Not look at a specific graph of a specific game sale history:

Sale prices for TAF as illustrated above are relatively stable.. they're going up only ever-so-slightly. If the collector market were actually growing significantly, we should see a more significant rise in the sale prices of one of the top pinball machines, but instead, we're only seeing a modest increase which is consistent more with an actual decrease in the number of buyers and available machines.
In short, there's not a whole lot of evidence that the pinball market is dramatically growing. The uptick in pricing is more consistent with a) less machines being sold and b) newer pinball machine prices pushing up the averages.

Quoted from PinballHelp:

I wouldn't call it an "explosion." There is a slight revival in pinball interest. And there are certainly new people coming to the hobby, but I still think pinball is a "retro" hobby, that typically does not appeal to the mainstream. Whenever news media reports on pinball these days, it's still one of those, "Hey, whatever happened to pinball?"-type stories.
I think the pinball market is changing. Games are going into peoples' homes now instead of on location. What we are seeing is the maturity of the collector market. Now that people can find information on how to repair and maintain their own games, more people are collecting and restoring games. I've participated in the Texas-based pinball festivals for the last 3 years. I think there's been a small increase in attendance each year, but it hasn't been "explosive" IMO. I think pinball enthusiasts are getting more aggressive in collecting; I think pinball enthusiasts are (on average) hitting that "sweet spot" in age and lifestyle where they have more disposable income and time to get into the hobby. I do not think it's mostly young people buying NIB Sterns.
I still think pinball is a fringe hobby, and will probably always be - nothing wrong with that. I think if it really did "explode" in terms of interest, most of us collectors would be a lot more upset over pricing and availability of machines. If the industry really did take off, it would be more likely that games would be on location instead of in peoples' houses. If there was an "explosion" in interest, we'd see arcades and operators ramp back up. I still don't really see that. There may be the occasional retro arcade in various areas, but I also think that's more of a labor of love by a collector than a business venture. Look at Dave & Busters... the biggest franchised coin-op outlet and they basically don't care about pinball. When they start filling their places mostly with pinball, then that might be a sign things are exploding.