There are many reasons, but companies that want to be on the Pinks have for the most part always been on the Pinks. Generally they aren't interested in trading. Some only use the listing to facilitate their employee options plans and the like; there are no shares available to the general public.
As a matter of fact, the Nasdaq originally listed on the Pinks. Nobody even noticed. Wouldn't have done any good, because no stock was available to buy.
Do you know why these companies choose to remain , or move to the Pinksheets ?
However, CMKI, as it was then, was simply delisted from the OTCBB because it failed to file.