I was evaluated by two US transplant centers that function under a government-regulated evaluation regimen, and spent more than a year researching the process.

Neither would proceed with any paperwork or testing without proof of insurance coverage specifically for transplant.

Honestly, I'm not especially concerned with edge cases like "is it possible to get a transplant without insurance if I offer to pay cash?" or questions about what a transplant really costs.

Those are irrelevant academic questions for the vast majority of transplant patients.