art is usually stolen and then held for ransom, as the ability to resell most work is too difficult for the average thief to coordinate.
http://www.artloss.com/Default.asp

i would think the average multimillion dollar art heist is beyond the abilities of the "average theif"

actually most art thefts are performed by what i would call average thiefs. security at museums is very poor for the most part and the thieves are not those found in works of fiction. i recommend this...

hmm... if the average thief can steal, on average, 1.3m/heist (given that this story constitutes the average theft), then how is it that so many of them just want to hold me up for my ipod and wallet or steal my car stereo?

also, who are the high-end thieves (above average)? man, the thomas crown affair really fucked me up.

take the case of the theft of the scream in oslo. two average thieves put a ladder against a wall, climbed it, broke a window, climbed in the museum and took the painting. museums do not have sophisticated devices to keep the crooks away. take the case of the isabel gardner heist. two guys dressed like boston cops, knock on the door of the museum, which is really a mansion, and tell the guard that they need to use the phone, they proceed to tie up guards and steel several hundred million dollars worth of art. sophisticated art thieves? not according to experts who believe that the crooks wanted to ransom the paintings.