I don't know how you can possibly construe the consequence of government regulation to the failure of the free market but you are ignoring the real issue at hand.
The FDA has killed thousands if not millions of Americans indirectly through overregulation. A major flaw of government lies in the public's tendency to blame lack of regulation on the government but not the negative consequences of regulation.
For instance, back in the 70s, the FDA banned beta blockers for close to a decade despite the fact that they were already legal in Europe. They did this out of fear that there was not enough publicly available information about the consequences of beta blockers. If there had been 1 death from their use, it would have been the FDA who was held responsible.
10 years later, the FDA approved the use of beta blockers and remarked that legalizing their use would save thousands of lives every year. So indirectly, the FDA basically killed tens of thousands of people by preventing access to medication sooner. They did this because the government is not held accountable for the negative externalities of their actions like businesses are.
But let's analyze your claim specifically that is a move of big pharma to take advantage of Kratom. This claim is similar to the claim that big pharma is the sole responsible entity for the dramatic price increase of the EpiPen.
That ignores the responsibility and power that the FDA has in establishing a cronyist system that would not exist without government intervention in the market.
If you want to read more about it, Scott Alexander (a leftist) details why the rise of prices in American medicine are the fault of the FDA and the government, not the free market.