First, as sibling comment notes, this is actually quite mild in terms of business continuity planning because unlike actual "hit-by-a-bus" issues, you have many

First, as sibling comment notes, this is actually quite mild in terms of business continuity planning because unlike actual "hit-by-a-bus" issues, you have many months of lead time to prepare for it. Second, your choice is not "one year of parental leave" or "perfectly performance from the person with a baby at home". Having a young child is a huge life event, parental leave or not. So, you can eliminate the most competent cross-section of the employable demographic (age for having children is usually past the point when someone is junior to the point of being useless, but before cognitive decline becomes an issue). It's a hard problem, so you have companies struggling with it like the Gates foundation, here. Since Canada is doing fine, perhaps instead of asking rhetorical questions you should read some Canadian HR journals?