From the transportation perspective, Toronto is probably marginally better than Vancouver for families.

You're more likely to require two cars in Vancouver than in Toronto as the combination of the Greater Toronto Area public transportation options cover a wider area than Vancouver's.

That is simply not true. If you are in dt Vancouver you can get pretty much anywhere walking. Not the case for Toronto(even downtown) due to city size and climate

I'm not sure why you're suddenly restricting your "two cars per family" point to the city downtown cores alone.

But sure - if we change frames then both city downtown cores are either easily walkable or extremely accessible via public transportation, hence ceteris paribus neither family (living in the downtown core) in their respective cities would require more cars than the other.

How long will you walk from Stanley Park to the border of Burnaby? By that logic, you can get anywhere in Canada simply by walking as well.