It may just not be very cost effective for them.
If you have companies buying millions of the other switches, and then you have smaller operations buying thousands of the clears, well, is it worthwhile to keep producing the clears? You have to think about the overhead and production costs that can be spread out over a large production run. It could also be that they is an issue effecting the production of the clears. If they had molds break, or some equipment wear out, and they're having trouble replacing it, then they'll not be able to produce like they were before.