I've done bonsai for the the last 7 years? No matter what happens, they all eventually die
The main reason none survive is that I demand on raising them from seedlings, so that they'll have been with me their whole life. Unfortunately, the younger the tree, the more fragile.
I have 3/5 maples left from the summer, but two of them really aren't looking that great. I'll try to shoot a couple pics of where they're at (they're less than a year old).
Next spring I plan on raising a good 25-30. I have two very large mother trees that give off hundreds or thousands of seedlings every spring.
The problem is in how slow they grow. Bonsai is basically a lifelong hobby. Everything else in your life will change many times over, while your bonsai trees slowly crawl along.