Perhaps my error was in saying that the specific conditions that the OP listed would result in financial ruin.

My experience is anecdotal from close relatives in Alberta having severe diseases early in life. Their drugs and "required care" was expensive and not entirely covered by their private insurance. Their private insurance had caps (annual and/or lifetime), and after, their medical history made it difficult or impossible to get private insurance with adequate coverage.

The bills were significant, but maybe each province has programs to cover the difference for those that cannot afford the bills?