Here's some info for you :
'A lot of common cold viruses are from the coronavirus family and we do not gain lifelong immunity after being infected by them. People who have been infected with another type of coronavirus, severe acute respiratory syndrome (SARS), can have two to three years of immunity, so it really does vary.'
You may have a point, though I'm no virologist. But the most often stated reason the likes of the rhinovirus, which is what most commonly causes the cold, is such a persistent problem is supposedly because it's particularly resistant in the sense that it rapidly mutates - resulting in a great variety of them flying about, with you catching a new one every year.
However, even this being the case, the reason there's no overall cure for the family of cold viruses is because, regardless of how shitty it can make you feel, it's never a serious infection - meaning it's far more profitable for the shameless shitbags who run big pharma to sell products that treat the symptoms as opposed to developing one.
Then again, the profits of big pharma are also the reason that the Soviet Union never developed a cure for anything.
Bottom line is immunity to Corona virus is certainly not a given yes. It's new, needs study time.
This is also something I've been saying myself. Though it's pretty clear the vast majority do become immune, at least in the medium-term.
We can argue around the fringes of this point as much as you like. Well, I actually can't really be arsed. As the bottom line is that this isn't fucking AIDS. Barebacking can be.