probably some combination of tall buildings, stupid electrification standards, and dangerous weather (#1 tornado capital of the world baby!) making house fires worse and more common
I looked at some stats because I was curious after this, more common yes, worse no. The US has a very high number of house fires, but a very low number of deaths per fire, and ends up pretty average on fire deaths per capita.
Presumably this is because we’ve taken these measures to make sure people can get out when fires do happen.