I agree about deductibles but "where all the rate is" doesn't work out IME (grew up in the insurance industry, worked in the insurance industry, step-father-in-law is our insurance agent so still have access to recent information, etc).
It's not uncommon for homes insurer's to require certain deductibles the dollar amount being the better rather than a percent often.
Then there's restrictions based on your exact area be that just your zip code, your county or region. The insurance company I worked for in my county required everyone with a wood roof to carry a 2% Wind&Hail deductible for example. Places prone to certain issues may have requirements as well. I know barrier islands (TX was the main one I dealt with, ETA when speaking about barrier islands, I dealt with close to 35 states in total) Brazoria County for instance had mandatory requirements. This is just me pulling information out of my head from what I remember.
In addition on homes the difference between some of the deductibles doesn't always amount to much on the premium. It just depends.
On the auto $500 deductible being very common well sometimes bumping yourself up to $750 didn't really amount to much at all, or if you were at $750 (or thereabouts) bumping up to a $1,000 didn't make much difference and truthfully sometimes increasing your deductible increased your rate.
I def. agree with looking at someone's deductibles but there's a ton of back algorithms at play such that going as high as possible isn't as cut and dried as thinking the insured is carrying the most burden so the insurance company will give them a break on the rate nor is it always possible for someone to reduce their deductible.
Good advice though is to check back with your insurance carrier (be it your agent or company itself) periodically as things change in one's circumstances and home. Re-evaluating what your policy has should be done every now and then.