It was at one point and luck didn't get us to the point of it being much less deadly
It can be. Same for fevers and the flu.
Take some bio classes
I have a biochem degree, there may be a small handful of deaths from the adenovirus (disputed) but they are exceedingly rare
it used to be deadly, but thanks to vaccines we can go through it.
There is no vaccine to the common cold, you're thinking of the flu
until they find a vaccine then all of a sudden it will become "deadly" or so the vaccine pharma will say and the sheep will all chant colds are deadly get vaccinated