I'm gonna have to agree with you Cry, demos just simply presents what the modder has worked on the pass time, but they don't always want to continue it because of motivation, etc. So they call it a demo so they can make it look like it's only the beginning of it.
When I played the demo for Amnesia before I got the game, I thought that it would have been the beginning of Amnesia once I bought it. I became disturbed when I become lost playing, giving an extra taste to scariness: When the expected does not happen. I've played a few custom stories that did actually have that, but the rest of them also didn't presentate them too well either. So I could never know which ones will be the good ones without playing them all. I decide to look at comments about it from other people if it doesn't appear good, but sometimes people just want to make the modder happy by saying it's good, so when I try it, it would be a piece of crap. Not like I'm saying they all are, but they usually have at least one thing interesting about them.
When it comes to modding, my greatest motivation is you, Cry. To watch your funny commentary when playing custom stories really motivates me to have you play mine. I've never released one yet, but I may be getting near to one, so I hope you play it when the time comes. Thanks for reading.