Couldn't agree more with this post. In the US there are a lot of wheel thrown pots because they are easy. To me "rustic" pottery is just a fancy way of saying "to try to hide mistakes". Slab built pots are extremely hard to do well because they show flaws. And the larger the pot, the harder it is to both hide the flaws, and deal with the natural variability that comes with ceramics. I have almost no trees that would fit in a pot smaller than 9"... and most of my trees (which are not all that large) need at least 18" pots. I'd say that 75% or more of pots that I see being made are too small for me to use on any of my trees. To be honest, many "bonsai pots" I see being produced are (at least in my eyes) not suitable for bonsai of any size or type.
I am planning on buying my own kiln and making my own pots because I simply can't find enough good slab-built pots. The good news is that because I don't have to sell my work, I can take the time to do the job well... which may not be practical for a commercial potter who knows they can sell three cheap wheel-thrown "rustic" pots in the time it takes to make a slab-built pot with tight tolerances.
It is a strange thing with Western art aesthetic, where people start by making splashy flashy unpolished work, and then perhaps get around to mastering fundamentals down the road. Some of the potters whose names have come up on this thread have difficulty even with basic symmetry - like symmetrical foot placement on an oval. Not going to name names, but I am not impressed with the American bonsai pottery scene taken as a whole. There are a handful of exceptional potters who consistently sell good work, but most of what I see I am not impressed by. I just watched a video that featured a Japanese potter whose entire job is just to finish high-end Japanese slab-built pots. In other words, other potters send him their raw unfired work and he removes all the flaws - every fingerprint, mark, sag, line, scratch, etc. Is there a single American potter who is even aware that such finishing work is done?
How many bonsai that are at the US national show are in American pots? Find out who those potters are, and you will find your good potters. If I were a potter, my first goal would be to get one of my pots in the national show - and better yet to win an award with a tree in one of my pots.