I think one of the biggest public dangers a short story writer faces is ignorance. Now I'm not saying that everyone should know everything. Nor am I calling anyone who doesn't read/understand short stories stupid. But I am saying that short stories are a topic not widely discussed which therefore leads to a lot of misconceptions.
What do I mean by not widely discussed? I mean people just don't really talk about them. Period. A TV show, for example, is something widely discussed. So even if a person never watched TV at all they could probably give a fairly accurate definition of what a TV show is and probably explain to some degree how a TV show differs from a movie. It's part of our culture and, therefore, an understood entity.
Short stories are not a large part of our culture. At least, not in the same way books are. The term itself (short story) seems somewhat self-explanatory. The reader feels no need to research the purpose of the short story because they already feel like they know what it is. It's a story. And it's short.
Well, a book is a story, no? Would you describe a TV show as a short movie? Of course not. There is no way I would classify Star Trek episodes as the same type of entertainment as Ben-Hur. People get TV shows and movies. They understand the premise of each and don't expect them to be the same.
Most people don't get short stories. I think the average reader goes into shorter works expecting them to be like a book. So the enemy is not really the short story and it's not how much the short story costs. It's the ignorance.
If short stories are ever going to make a comeback in this ebook revolution, I think that people who do get short stories need to make a concerted effort to educate readers. Not everyone has to like short stories. But people should or shouldn't like them for what they are, not what they thought a short story should be.