Frame work:
More bar skeleton:
Here's what I think. People will buy anything that is of high enough quality and has good enough advertisement and has little enough competition that it isn't drowned out.
There has been very good B+W work, but it is often drowned out in the market by so-so comics that are only in B+W because a big publisher wouldn't pick them up and self publishing is much cheaper in B+W. The color in comics often signals quality because it was worth shelling out the extra cash to print in color. Color basically means someone thought these comics would sell and B+W comics seem often a financial decision rather than an artistic one.
Really if a big comics writer, such as our curator here, wrote in B+W, I doubt sales on that book would be low. That is because Warren Ellis has no competition in his niche, he's fucking Warren Ellis. You see a book by him, you will buy it. You see a B+W book by Joe Shmoe 1 vs. a color book by Joe Shmoe 2 you're probably more inclined to buy color because hey, more production value often means better product. Don't get me wrong...a lot of times it doesn't, we all know there's a lot of crap with high production costs, but c'mon, there's a lot more crap with low production costs.
Disclaimer: I'm not saying this goes for everyone, just that it seems to me to be the general consensus.