Why would they edge in on a space that doesn't make money? In other words, not every medicine is profitable (eg: commonly available herb).
Just multi-vitamins is a billion dollar industry and apart from pregnancy or perhaps vitamin D most of the claims are bogus.
http://slatestarcodex.com/2014/06/15/fish-now-by-prescriptio...
So the companies selling common herbs are doing so at a loss?