I think you are making the mistake of looking at it from ONLY the collectors point of view.
To the casino it is a business and represents money in their pocket.
As Pete pointed out below, don't buy em' and they won't make e'm.
I think you would be amazed at the amount of chips that are turned down by gaming that might be either a bit off color or tread too closely to trademark infringment.
If I recall correctly, one example was when Palace Station put out the series of "joke" chips
One idea that was turned down by gaming was....

Where do you get virgin wool from?
The answer was.....Ugly sheep