> There's bunch of cheap stuff coming from all over the world.
Said cheap stuff from everywhere cannot be legally mass-imported into Western countries (and that for good reason).
> Collusion on that scale is not possible
Oh it certainly is. The "old" insulin may be produced as a generic but the new varieties (as described by the article) are patented by a few companies.
In addition insulin production is extremely expensive compared to simple pill pressing as you need bioreactors and GMOs to produce it. Many generics vendors opt out of that complexity.