Bonsai on the movies are Junipers, and some are really good ones, at least real ones... And well, on 1984 Bonsai art was getting refined, and popular on the other hand.
About the business, very few artists sells good "finished" trees ot there, and well, they are recognized on the art.
Bonsai are not much different than paintings on that, very good artists make high grade trees, that worth a good amount of money. However it takes them many years to master their abilities and techniques, and being able to show those results.
And of course there is a market for pre-bonsai material, that are trees that were given some potential, aiming to become some day an Bonsai, like a trunk thick, with already some movement on it maybe, some positioned branches for you to choose, etc...
However people who buys it MUST KNOW that it's up to you to turn it into Bonsai, and that's the point right?
I like the process as much as the result...
Honestely, to start a Bonsai business, you must know Bonsai, and that's a long walk.