dingdingdingding! It's hard for even the better promoters to find people willing to shell out $40-$100+ for two or three days so they can sit there and listen to a seemingly never ending chorus of "what a ripoff! I can get that cheaper on ebay! How much will you give me for this 1989 Fleer factory set? These were in your $1 each/12 for $10 box, will you take $15 for these 26 cards? No? Guess you don't want to sell any cards." I know our local monthly show advertises 40 tables, a lot of months there are about 15 actually sold. I know one of the guys that does it lives about 3 hours away, so he pretty much rents a hotel room for a night. Figure 2 $75 tables, about $50-75 for even a Motel 6 around here, hit a McDonald's on the way in for breakfast, a sandwich for lunch, grab dinner at the sit down restaurant near the hotel, breakfast and lunch the next day, you could be in $200-300 pretty fast. Now you're behind the table with everyone expecting ebay prices, which are often about 50% of book, meaning you'd better be into this stuff for 10-20% of book max. Even if you get double your cost on every card you sell, you still have to sell $400-600 of cards just to cover your costs. A 40 table show with moderate foot traffic does not make that an easy thing to achieve, even when the economy was solid. That hasn't even covered gas/transportation costs, or the possibility of shoplifting.
As others point out, ebay adds a huge change. You may be the only one at a show or in the area with that Ripken insert /1000, if someone wanted it before, you could set a price and someone would likely buy it or negotiate a price close to it. Now there are 7 more of the same card a mouse click away. Everyone who opens a pack of cards can be a dealer with an audience of millions. People can search for exactly what they want. While many of us enjoy digging through bargain boxes, there are people who don't want to hear "if I have any (insert player name here), they'll be in those boxes", as he points to 2 double shoe boxes that even if they started out alphabetical or by sport, have often been dug through and mixed up better than a deck in a Vegas casino. They don't want to spend 15 minutes at a table only to find absolutely no Carlos Beltran cards.
Then there is the Murphy's law. This often applies to vintage dealers. You have x amount of room to display. What do you bring? Nobody has asked for 1964 Topps singles for over a year, except for a handful of HOF'er cards. You leave those home to make room for the nice batch of 71 Topps you just picked up. Sure as you're sitting there, someone will come up and ask 'do you have any 1964 Topps?' You tell him they're at home, give him your card, well, they'd really rather see them in person vs an emailed scan. He asks if you can bring them to the next show. You tell them you'll bring them next month, you do, he doesn't show up and no one else gives them more than a passing glance while asking if you have something else that you naturally left at home for logistical reasons.
