Someone else might need to have a secure communication channel with his wife. I never read the comment as "I can't communicate securely with my wife", more "My wife is not in the set of people with which anyone can communicate securely" (because secure key management is hard).
All security decisions boil down to some calculus of risk, impact and cost. The most sensitive conversations that my wife and I typically have remotely aren't ones that justify the cost (both in terms of hassle and $) of carrying a secure device around.
Personally, if I were in a situation where I was remote and my physical safety or livelihood could be compromised from an email, my wife and I would probably suck it up and run around with secured netbooks or something. In my case, I don't see that risk/impact calculation adding up to requiring PGP.