Agreed that some of the liability requirements in the US are crazy low, also considering how litigious many folks are. So it actually is a bit of 'Murica as Oldtimer wrote. However the minimum 3rd-party liability requirement in Ontario is actually only $200k, which is better than $30k but also too low.
A nasty side issue: in Ontario, you can't purchase supplemental liability insurance, and it's always the responsibility of the owner i.e. the rental car company if you're renting. Often they only have the minimum $200k coverage. If you don't also own a private car, with a rental car rider to bump up your insurance, you're stuck with the $200k liability coverage. And you're also stuck with the same CAD$200k coverage if you take the rental car into the US -- inadequate.
It's a big concern for me as I rent often and don't own a car. Also an issue when I was thinking of a road trip to the US for TFC games. And almost no Cdn car rental agency has a clue about this. If you ask, they'll happily sell you expensive LDW which you don't need if you have a good credit card, but they won't know anything about the liability problem.
In the US you can usually purchase supplemental liability at a fairly decent price from the rental agency.
That concludes my TED Talk.
https://www.myinsurancebroker.com/in...ce-in-ontario/