Most of these displays are powered by run of the mill Windows machines. Often they are just standard off the shelf hardware, which when packed in an enclosed space with other electronics, and wrapped with cardboard, doesn't last too long. Even the screens are often just standard bigbox store TVs, although some manufactures do make displays specifically for digital signage (for 10x the price).
We have our own hardware running a custom Linux distro, and it's designed to operate in these sorts of environments. However not all accessories are. Right now we are trying to figure out what to do with a camera which is only designed to operate in environments under 50c where we keep having hardware failures.
The budget for installations like this most likely comes from the marketing department. So instead of paying for print ads with no idea how well they convert, the money is spent on digital signage which can at least track basic data like the number of impressions. Unfortunately in this case, it's probably treated like a win as they get more analytics data than they did before (impressions, door opens, open time).