These days, you walk into any American supermarket, you can find kosher chocolate bars, kosher jelly beans, kosher all sorts of stuff. I understand why the gummy worms aren't kosher, they contain gelatin, and most gelatin isn't kosher.
But what about chewing gum? Is there some ingredient that's usually not kosher? Are the market forces just not there?
(I'm not asking "what ingredient makes Wrigley's non-kosher"; I'm asking "why hasn't it been worthwhile for Wrigley's to get an OU?" [Using Wrigley's and OU as examples of a major gum company and a major hechsher, of course.]