No, they don't go missing. Socks mate in the washer and give birth in the dryer.
How else could you explain that oddball sock that shows up every once in a while when you just know you've never bought any like that?
I have a place for odd ball socks. Only after enough time has passed(I’m not sure how I determine that), I throw out the ones I’ve given up on. Only to have the mate show up in the next week’s laundry. And that doesn’t even take into account that I have a dog with a sock fetish and it is not unusual, if we have a particularly large amt of odds, to look under the bed and find 6 or 8 socks she has ‘collected’. But that must be done when she is outside because she is sensitive to someone going into her private stash in her presence.