I think the issue (and again, part of this comes from Pinside) is that you have this stigma that if you are not in the upper Midwest region (especially Wisconsin, Michigan) people tend to talk down to other sellers/collectors on the assumption that they are "better" with their state of pinball. On more than one occasion by multiple members I've had one guy talk to me about all of his PAPA stuff and current rankings and how X is Y and another one in a thread (who has posted in this thread coincidentally) state we're in a pinball "wasteland." Now we have this pricing question.
Here is the thing. Whether people like it or not if game sells for X money WORLDWIDE that is what the value is now. Regional pricing only makes a difference if you stick to regional sales. This is a worldwide site and if the games sell for higher values (and they will also do that at shows) then that is what they are worth.
Shipping isn't a thing anymore. The reason the Bally games have gone up is because all the DMD/bardcade/hipsters raised the market value on that stuff to make most of them unaffordable, so everyone went to the next sequence. It's only logical in terms of how patterns with pinball and pricing/demand work.
Now I own 3 stores and I also sell a LOT of console stuff. Whereas regional sales apply to "Super Mario World for $34.99 in Nashville" to "Super Mario World for $19.99 in Cookeville", the idea is to go where the most money is to sell your item. If you have a store in Cookeville ebay is your best bet to sell it. In Nashville we can get more money than ebay for most of the popular stuff.
Pinball reaches far beyond the upper Midwest. Nashville tends to be not as interested in competitiveness (this goes even down to fighting games and tournaments) but we have the players here for pinball and other stuff, however in my eyes (especially as someone who has played as much pinball as I have) if I am not having fun and would rather do other things, I don't see what having to prove to anyone would matter. I am perfectly happy collecting my stuff and doing my thing and most other guys are as well, it's the outsiders that like to come in and make assumptions. It's not a dick measuring contest. People don't understand that Tennessee has a lot of private collectors with a pile of games. With as many pins as I have I don't even think I have the most in my own TOWN if that tells you anything, and I live outside of Nashville.
Bottom line is pricing has gone up on this title. Medusas have sold for over 2K recently and new playfields fuel the interest. The days of the 90s and 2000s are not here anymore. With higher demand in machines come higher pricing, however if most of the barcades start closing, the pricing will drop again.