What exactly are you insuring with these policies?
When I looked at it many years ago, it seem to be for an excess that I'd be liable for in the event of having an accident. (The amount varied between $2K & $5K and the premium obviously varied on that too).
According to my renters their excess (which they call the deductable in the US) was $2K and they'd only pass it on in the case that I did something really stupid.
Not that I'd seek to rely on that, but I was happy to run the risk of a $2k bill if I damaged the aeroplane on the six hours that I was going to be flying it.
Is this all that is being insured with this policies? For most people able to rent an aircraft for a few hours on a US holiday, I wouldn't think that a $2-5K bill was going to ruin them financially, and therefore worth insuring.