You're ignoring the middle ground, because that's the thing that was destroyed. The expert potter is still in business selling bespoke products to millionaires.

It's the one who might have done it for 15% more than the mass produced product who is gone, because we added on top of that so much bureaucratic overhead that the final price ends up being 100%+ more instead of 15% more and that exceeds what ordinary customers are willing to pay.

Why would you buy a product for 15% more, unless there's a compelling reason to do so? The mass produced ceramics are high quality, durable, come in a variety of shapes, colors, sizes, etc. People buy hand-made ceramics for the aesthetics, and to have something that's more unique.

I think you greatly underestimate how much cheaper mass produced goods are than artisan made goods. Op's choice of ceramics is really good. Machines can produce thousands of plates in the amount of time it takes an artisan potter to make dozens. The potter's source of clay may be limited, or they may have to pay a lot more because they buy in smaller quantities. They have to pay more for transportation for the same reason. They have to pay more for distribution for the same reason.

Bureaucratic overhead may play a part in this, but overall it's a small one that gets lost in the scale of mass production.