The retro scene became vastly over-inflated... which led to a more "accepted" view of everdrives and such other devices....
Honestly, I don't know how to feel about that. On one hand, I'm glad I can just buy an Everdrive, but on the other, I know there are people who just get one, download a whole romset and will proceed to brag about how they've been *insert console name here* owners and fans since their early childhood, despite the fact that they're 13 in 2017. One thing is sure, though. While I used my older flash devices for homebrew, I use Everdrive for convenience. Having all of my games on a single cartridge means I don't ever have to dig anything up.
I look at the NG prices on eBay and think possibly it's gone a tad TOO far towards retardville... when a once common $15usd AES Cart is going for at least $100usd... then you know it's going to shit...
That's the argument I was about to use, and it applies to all platforms. Soon you'll see loose MVS cartridges glued shut in acrylic boxes, going for $1000. But you know it's good stuff, because it has been graded by a bunch of random dudes calling themselves The Authority something or other. I remember getting Judgement Silversword for the WonderSwan, and back then it was $100, which I thought was a lot. Saturn's Taromaru back then went for $300 and Silvergun for about $100. Now?
Silversword - $400 to $800
Taromaru - $800 to $1100
Silvergun - $200 to $800
Of course there are still people who will try to sell above even the highest price. Right now there's a Silvergun for sale for about $1300, seller claims it's sealed, but the post stamp sized photos show an open game.
I can still pay $100 ~ $200 for a single arcade game, more often than not a game + mobo, but I'm not surprised people are investing in NeoSD and other multi-kits with the prices of some, say, CPS2 games. Why spend a mountain of cash on one single title, when you can have them all, and that includes buying A + B boards and the kit. CPS3 games are overpriced as well. Everything on eBay is priced wrong. Some years back I could have bought VF4, Evo and FT for $10 a piece. Not on eBay mind you. The current price for the first VF4 is about $70. I won't even mention other titles, which cost as much as a net DIMM.