@BobbyLane is right; you can definitely find deals elsewhere. Many of the other posters are also right; they can be difficult to find depending on where you are. Like many things in Bonsai; it depends.
However, one key point that no one has mentioned is the fact that even if the sale prices are “higher than you can find elsewhere”, buying from Bjorn or Ryan or Randy or Todd or Andy, etc. supports your American Bonsai artist/collector. I’ve gotten to know quite a few of them(and since I’m in the venture capital landscape, I openly discuss financials/organizational structure/exit strategies/valuations, etc. with them and have on multiple occasions been dead on as far as where their businesses stand financially). NONE of them are getting rich off this. Not even Ryan who seems to be the standard to mock/pick on for high prices. These folks are truly doing it for the love of the profession. Some even have higher aspirations(such as conservation work) that are beyond the field of Bonsai, but nonetheless improve all of our experiences. And let’s not forget the difficulties and cost(mentally, financially, etc.) that these same professionals have endured and continue to endure. I know of one professional personally who almost left the field because of the significant loss of material due to unexpected inclement weather this last winter. And of another who is preparing to leave the country due to the lack of ability to support their family.
Ultimately my point is simple; if you are able and willing to support these professionals, do so as a rising tide lifts all ships. If you are not able or not willing to, at least don’t assume negativity or nefarious reasonings for their (in your opinion) higher-than-it-should-be prices.