There are many types of fires that can be extinguished by sprinklers but their primary function is to give occupants more time to escape. A common type of fire

There are many types of fires that can be extinguished by sprinklers but their primary function is to give occupants more time to escape. A common type of fire that has emerged recently is lithium ion battery fires. Some jurisdictions have so many it is an epidemic. Sprinklers do nothing to combat lithium iron battery fires, other than slowing the growth of secondary fires. Honestly I don't think secondary exits should be required for small, low-occupancy buildings (that's a problem we solved with fire escapes but they're "ugly") but at the same time I don't think eliminating them would solve any accommodation availability problems. For example, in the floor plan included in the article, eliminating the secondary egress staircase would add less than 140 square feet (varies by jurisdiction/occupancy but that floor plan looks like 48" wide stairs with 8 12" treads and a 48"*96" landing on each end) to the floor. In the article itself the author (rightly) asserts that adding a single bedroom to the design in a size acceptable to the market requires approximately 180 additional square feet. So all you'd get are bigger bedrooms and/or closets, or the addition of a single tiny bedroom. Indeed, in the example given in the article it would be almost impossible to add an additional bedroom. But one or both of the apartments could be given palatial bathrooms...