Well, I've got all mine, unless another booster is available that I don't know about. One thing about vaccines is that you know exactly who got them, and who didn't. This probably makes it a lot easier to study.
And I'm willing to believe that some childhood exposure to pathogens is beneficial, but I don't think we know how much of a good thing is enough, or too much.
Do you think that we’ve discovered and cataloged the sum total of milder pathogens that protect against worse illnesses in a lab? Got all mine means “got all the ones we currently know enough about to develop a vaccine for.”
No, I don't think we've discovered the sum total of milder pathogens.