For instance, if someone was vaccinated, but then exposed and was lucky enough not to develop an infection from their exposure, are they immunologically better off as a result of that exposure? I think they probably are, because my understanding is that's how the earliest vaccines worked (exposure on a small enough innoculum to avoid infection) but I'm not an expert, so would love to hear more about this & whether there's a name for such an immune effect when it happens in the wild.
But for that, you are, at most, looking for the occasional transient exposure - not the bombardment that one is getting right now.
Also read a summary of influenza challenge studies. People exposed to low doses often seroconverted asymptomatically.
I feel it's plausible small exposures after vaccination would build more protection.
It also depends on how many particles it takes to get you sick. Norovirus is only 7, which is insane and also why it spreads so easily. Hard to have just an exposure to that!
I suppose for some version of "eventually" then everyone would likely expect to get a breakthrough case eventually, but even so the vaccines should drastically reduce the number of times one expects to be infected, so still risk would be reduced, even if it wasn't for breakthrough cases (although it appears that vaccines reduce the risk there as well).