I agree with this wholeheartedly, but Illich called for the abolishment of social institutions altogether, not the improvement of them.

I'm quite suspicious of such calls for abolishing institutions rather than reforming them - whether from the right or left - because they are often just cloaked attempts to replace those institutions with their own preferred "purer" institutions. In the case of Illich, his preferred institutions would seem to be somewhat connected to his religious work as a priest.

> dislike the US health care system, and think we should move from private insurance to a single payer model

Single-payer/Medicare-for-all is just advocating for reform of the health care system by removal of the pathologies of private insurance, not the abolishment of shared risk pools altogether. It's an evolution of the current system, not the destruction of it.