The term is Original Antigenic Sin. The vaccine "trains" your body to respond to an antigen in one specific way, thus allowing variant mutations to face a lower antibody response by the body.
A doctor explained it to me this way - its WWII, and you saw Poland overrun by German blitzkrieg. So you develop a defense (vaccine) against the Panzer I. You train your entire army to fight a Panzer I.
Later on, you find the Germans are now indeed invading your country (body), but not with Panzer Is, but with airborne troops or Panzer IVs. Meanwhile your troops are all at the front lines expecting Panzer I. If you had kept your natural defenses, you could have muted the worst of the attack. Thus you get your ass-kicked.
I think it’s even worse than that!
The mRNA causes/programs some of your body cells to produce the spike proteins.
As long as it’s not certain body cells, like heart cells, liver cells, etc, your are okay, for a while.
Eventually, the cells that get reprogrammed, or additionally programmed, to produce the spike proteins, die off and are replaced by non-programmed cells.
The body’s immune system then gets used to having the spike proteins around because they are everywhere and are made by the body’s own cells, so the immune system quits attacking them because they are part of the body.
So, when a new variant comes along, it’s defenseless all over again.
Just my opinion.......................
An alternate military analogy is France’s inept use of tanks in WWII. The Germans developed armored division Panzer warfare, while French doctrine was to disperse their tanks among the infantry as infantry support.