Like any insurance product, home insurers price their product based on what they would have to pay out for loss. So if my home value is up, I expect my insurance cost to be up proportionally, regardless of any other factor like an increase in the risk.
And, seriously, if you live in a place where your costs regularly exceed those experienced by people in other places, perhaps it's time to move. What you paid 20 years ago for your house is a sunk cost and should not play a factor in that decision, because it doesn't sound to me as if that loss will ever be recouped. Find a place with costs more closely aligned to your actual current means and move there. You may have to downsize or rent an apartment, but you need to staunch the ongoing hemorrhaging.