Last I read online maybe 3 years ago from the NintendardAge website people someone had written that ebay auctions have dropped to where it was like 80-85% BIN only, the rest are auction or auction w/BIN slapped on it. All things video games have had it happen to them, but thanks to stuff like those storage locker shows, picker programs and the rest the cancer has spread to anything more or less 'interesting' made from like the 1980s and before. It wasn't too many years back that getting a box with a game was part of the price, not in addition to (same with manuals+maps, dust jackets, and asinine enough even little plastic baggies.) Things have just degraded horribly and the arcade stuff such as Neo-Geo which is more like in setup a console anyway gets the game shitty treatment. Loose MVS/AES carts, throw in a manual/mini marquee+art pack, retail aes box/cardboard box with bubble bag and you're asking for an exponential price increase.
I used to be all about having manuals, I enjoy the dated materials as much as the useful information within them intended by the developers to help drive the story but also keep the secrets while spoiling nothing (unlike a faq) but I just don't bother anymore unless I can get it cheap enough to excuse it or it's included by a good person. For the 20 odd MVS games I have, only 20% of them I have the marquee for, and just 1 is a complete kit (neo turf masters) because the price was the same as getting the loose cart alone if not lower. My latest pick up was $78 shipped for 8Man with the Mini Marquee and I was thrilled as the game on the usual ebay troll BIN goes for $100 and a bit over.
Just to put it out there I do not list stuff as BIN on ebay only I find it distasteful but I also don't want to let some flipper garbage use me as a mark either. I research quality for quality the average price an item sells for, and I'll set it probably 10-15% lower but then slap the minimum 30% required BIN value on it as well. When people don't just ignorantly ignore my stuff (which I see using sold auctions) like idiots to pay higher my stuff moves pretty decently.