across the city are dowsed with gasoline (the elderly and ones with pre-existing conditions), and someone lights one on fire but there is no visible smoke until the building is well on fire and possibly lights its neighboring buildings on fire.

As a result, a catastrophic number of buildings across the city are on fire, only half of which the fire department knows about. How well can the fire department handle something like that?

tl;dr - imagine there are 2-3x the number of fires going at once and not enough water, fire hoses, or protective gear. How would the fire department handle that?