No cure so you gotta rest. Nose is stuffed so you gotta mouth breathe. Throat is dry from mouth breathing. Dry throat makes it painful to swallow. Pain keeps you from sleeping and recovering. Lack of sleep leads to worse symptoms like piercing headaches. Need to rest to get rid of the headaches. Headache and swallowing is too painful to rest properly. Lack of rest perpetuates headaches, nose congestion, dry throat, painful swallowing.
What is this BS
You’re only seeing the colds that made it through the defenses, without having any means of measuring the ones your immune system successfully blocked or kicked out before they could take hold.
So your statistics are flawed.
And even then most of the ones that made it through/past the immune system are still eventually fought off again by the immune system. I.e. you don’t have to take an external antibiotic for every cold.