When I look at it, it seem to me there are really multiple 'markets' with the pinball ecosystem . . .
There are the deep pocketed collectors, who like to go NIB and get the latest and greatest. Many, but not all, of these folks are often willing to buy before playing. Typically, they then look to sell those games when out of space to go buy the next NIB. There are a few NIB buyers who are not deep pocketed and tend to churn games quickly to support their NIB addition.
The second group are those that like NIB games, but are more price conscious, they will go Pro, but often look to go premium -- if the game has shown itself to be a higher quality game. Theme can be more important to this group, as far as getting them to go premium, but they don't buy NIB as often as the first group.
The third group, are Stern fans, but those that rarely, if ever, get NIB game. They like the latest Sterns, but are not as deep pocketed, so they look to pick up the games in the secondary market. They like to play the machines first, since they have various limits in their collection. They are often looking to trade for similar games. Often some portion of the collection will be 90s DMD games, but they are more Stern oriented (really like blinding flashers and bright playfields)
The fourth group is the "Bally Williams die hards", these are guys with collections dominated by 90s B/W titles, with some other brands or late 80s games thrown into the mix. While they may have a newer stern or two in their collection, they prefer the B/W stuff (frequently say "stern flippers suck"). Accordingly these guys are rarely interesting in a game over 5K, unless a true 'A' title, like AFM, MB, MM, SS. Some of these guys will have an 80s game or two or even an EM game in their collection for variety.
The fifth group is guys who like old school games, like 70s and 80s bally and sterns. These 80s titles often make up a decent chunk of their collection. They often have the 90s B/W games and a few newer sterns sprinkled in, but they do dedicate a decent amount of their collection to the games of this era, that are often at a lower price. They often will have a couple of EMs in the mix, just because they like to be eclectic. In general they are price conscious like the previous group.
The sixth group are the EM fanatics, who typically rarely even consider something with a alpha numeric or DMD, they may mix in a newer game or two, but they are EM first and foremost. The whole NIB conversation is just noise to them.
Any of the groups (well maybe not he last group, unless it was juicy melons), could jump in a NIB game, if it is a must have theme for them, but other than the first two groups, most of the others are 'play it first' and 'buy it used'.
Not everyone will fit perfectly in these buckets, some sort of sit between. And obviously there will be plenty here on pinside who will totally disagree with this. But in reality the pricing of NIB games, for many, is not something they get too worked up over.