There are many more chip molds than you would think. When I visited ASM in Las Vegas a few years ago, I saw lots of molds. (Imagine an aisle at Home Depot with a shelf with what looked like around 20 or 30 "tops" and "bottoms" of molds.
Some molds are proprietary "house" molds, and have the casino name engraved in each chip cavity. The manufacturer will only use those to make chips on orders from that casino -- not you or me.
Some are privately owned and can sometimes be used with permission of the owner.
Some are not used because they have cups that are very worn. You can't put slugs into all the cups or you'd be wasting clay. So instead of 20 chips with each pressing, maybe you're making 14 chips. It takes more time and energy (think paying the heating bill) to make chips using that mold.
So it would be more efficient to use a mold where you get 20 perfect chips every time.
A few years ago, there was talk of creating a new mold. I don't recall who floated the idea. The low-end cost for the engraving was $10,000. (I think that cost was the ballpark for a mold manufactured in China, and there was some question about how precisely the engraving would be done.)
So if you're charging a couple of cents per chip toward the cost of making the mold, you'd need to make a half million chips with that mold just to make up your up-front cost.
If you are a casino owner, paying maybe $20,000 for a mold precision-made in the U.S. or Europe is an easy decision and can be recouped from one high roller. For us in the home market, we'd need to do the biggest group buy ever, and we'd never get that number of people to agree on what the chip should look like.
