I dunno. Selling short stories is certainly hard, but at least in SFF, there's also a lot of interest in finding new talent. I certainly wouldn't pretend that it's an easy path, but I also wouldn't discourage someone from pursuing it if that's where their interest & skills lie.
Keep in mind that writing short stories and writing novels are not just different "levels" of the same skillset. It's not like learning to play a half-size guitar before moving up to a full one, but more like learning to play a flute and then a tuba. Some of that skill is transferable, some is not. Most writers find that they have a "natural" length, and that to write shorter or longer than that requires a more conscientious understanding of their strengths and weaknesses, in addition to understanding how the change in format affects elements of craft like pacing, etc.
If you're just starting out, my advice -- and this may or may not work for you, but I think it's worth trying -- would be to just start writing. Get a feel for how *you* tell stories, and what sorts of stories they are. See how long they turn out, work on mastering that story at its chosen length, then start over playing again. Let yourself be inspired, and learn along the way.
Publishers in every field are always looking for new talent, and I certainly don't mean to discourage anyone from writing short stories. W need more short story writers, not fewer. I'm just saying don't write them because you really want to write a novel, and think writing short stories will make that somehow easier. It won't.
Even if you have a ton of talent, by the time you write a short story that sells, you probably could have written several novels.
About the only part of your post I disagree with is telling new writer to write stories and see how long they turn out. I think writing this ways delays more promising careers than almost anything else.
Stories should never just "turn out" a certain length. Length should always be fully under the writer's control, even from the first story. Good, publishable short stories don't just happen, and neither do novels. To get all the elements right, you have to control length from page one. Page one, in fact, should determine whether it's going to be a short story, a novelette, a novella, or a novel.
Every element, pace, flow, characterization, plot, description, and you name it, changes depending on length. A writer who just allows a story to come out at any length is probably not going to sell much, not because he lacks talent, but because his stories won't have all the elements right.
Stories don't want anything. Stories have no desire. Writers deliberately choose everything about a story, including length. When you sit down to write, you need to know whether you're writing a short story, a novelette, a novella, or a novel. Knowing this is the only way to get pace and flow correct. More, novels are not longer than short stories, they're wider, and if you don't add the proper width, you'll write a 100,000 word short story, not a novel.
Slush piles are full of 100,000 word short stories, and they never work.
Maybe "structure" is the right word. Each length has its own best structure. Structure is what controls pace and flow, mood and tone, and that determines width, and structure doesn't just happen. To get structure right, you have to know that the story will be roughly five thousand words, or twenty thousand words, or one hundred thousand words. Otherwise, such things as opening, middle, ending, climax, story arc, etc., are not going to happen at the right place and time in relation to the other elements, and width will be completely out of control.
I firmly believe that if a writer wants to write stories that stand a great chance of selling, he not only needs to be original, he not only needs to write well, but he must know what he's writing when he starts page one.
Of course, I think the same is true of novels. No one wants a novel that's really a 100,000 word short story, or an out of control novel that hits 300,000 words.
Too many writers also fail to control length in a novel, and then think the way to handle this is by publishing it as two books, which simply doesn't work. Duologies and trilogies, too, need a particular structure, and aren't just an overly long, out of control novel broken in half.
Anyway, by all means, write short stories. They're wonderful, we need more short story writers, and there's nothing at all wrong with writing them. But don't write them because you think selling them will be easier than selling a novel, and will somehow help your career as a novelist. Until you write a publishable novel, you have no career as a novelist, and don't know that you even can write a good novel.
You certainly may have to write three, or four, or seven novels before you write one that sells, and taking years away from this in order to write short stories will get you nowhere. I've known writer who have been writing short stories for more than two decades without selling one, all the while saying they really wanted to be novelists.
If you want to be a short story writer, then write short stories. If you want to be a novelist, then write novels. If you want to be both, the write both. But do each because you love it, not because you think one will help the other.
