Oh yeah. When I haven't gotten a card back in three years, I mark that name off my list (except for some elderly relatives who cannot send cards anymore). But, sure as sunshine, every year I get a card from people who I had completely forgotten about. I usually send out about 60 cards per year, but buy 75, in case of crap.
What's bad is when I get a card from someone whom I haven't heard from in, say six or seven years, and there's no return address on their card. I have long ago tossed their Rolodex card into the shredder. Then I have to call around to try to find if anyone else has their address.
Why do I go to this trouble for people I will probably never meet again? Why, tradition! All part of the holiday angst.
Black holes are where God divided by zero.