Perhaps it's somewhat pragmatic. Churches are built to last by the standards of the era, and they're funded by generational resources by people who want to make a legacy, but churches are still victims of disaster at the ordinary rate. Earthquakes seem to claim significant victims even to the present day: https://en.wikipedia.org/wiki/Proto-Cathedral_of_St._Mary

The Christian view of fire is, of course, multi-faceted, as the Holy Spirit is a force for renewal, rebirth and purification. No parishioner wants their home burned down, of course, but at the end of the day, those are simply buildings, and they're replaceable, and every demolition is an opportunity to remake something new and wonderful.