I think that the renter's insurance covers the deductible, or 'excess' in European terms, which is why it's so cheap. The whole issue of subrogation is another bag of worms with little hard information, presumably because people are bound by privacy agreements. One thing to watch out for is that neither of the leading on-line providers will accept foreign addresses, but instead encourage the use of accommodation addresses. I persuaded my insurer to put in writing that I was a foreign national living abroad, but they will still only correspond with my US address.
The point on courtesy cars is a very good one that should be noted especially since driving uninsured is a crime in some states. However it's largely a moot point nowadays, since the advent of Uber has transformed the utility of small airports for travellers like us in my opinion.
None of my 1000 hrs+ of renting has been in anything larger than a 172, but the point about the 182 makes sense. Have in mind that the West is largely high and hot in the summer, not to mention bumpy, and plan to fly at dawn. US airports and operators start early too, so the sort of 'opening hours' nonsense that we put up with in Europe are rare or non-existent.