I hate how this world works :/
The fact that there are 5 middle men is... more of a moat in this case? They've solved a complex, intractable problem profitably. Does this mean they're a 20-year company? Eh, not without some significant additional revenue streams or pivots into different areas, and to that point I agree with you about their vulnerability. But for the next 10 years? These are good margins building a business that only incrementally reduces the fucking over of the consumer.
The US accounts for 45% of global pharmaceutical sales. Even if they're limited to "only" half of the global pharmaceutical market, that doesn't sound like the worst position to be in.
"sooner rather than later" won't be in 4 and could take 8! years (that's seems later to me)
If you're concerned about their longevity it looks like they'll have plenty of cash to figure it out over plenty of time.