This seems too good to be true. Respiratory infections kill and debilitate a lot of people. If cranking up the innate immune system all the time reduced illness with no downsides, you'd think evolution would have done it already, but it didn't, which makes me think there's probably a downside, and the fact that the innate immune system is only cranked up when a pathogen is detected is probably because the downside is…
You probably know that antibiotic use is rampant in industrial livestock. But do you know precisely why?
Antibiotics aren't just given prophylactically to prevent infections; constant low doses actually *increase the animal's size*. The animals can put more energy into growing larger, and spend less on their immune system.