I think the best way to "prime" your immune system is to go ahead and let yourself get infected and let your immune system do it's work.I can see your point that that seems like an inconsistency. I think now that we are in the endemic phase, it is akin as to why I think it is important for everyone to get the flu vaccine. More immunity out there at a minimum means less severe cases and less time off which means less of an impact of flu/Covid season on healthcare and our community. We have this awesome immune system that we can prime and that helps everyone directly or indirectly as part of a strategy to mitigate the impact of the respiratory infection season. But I do think post omicron there is not a good argument for doing anything more than encouraging the vaccine, especially given the distrust and skepticism out there.
I've never had a flu shot in my life, and I don't anticipate getting one. Why would I? My life is half over and I've never had an issue with the flu beyond maybe being down for the count for a day or two. I honestly don't know if I've ever even had the flu because I've never been tested, but I'm sure I probably have.