IMHO the problem is the NOT infrastructure per se, it's the theoretical part that is cumbersome. If you now why you are doing something, it's easy to understand why you should not save the 'key' in the "Keychain" or sign random emails.
To use GnuPG correctly you need explain to average Joe concepts like:
* PKI
* Key signing
* Web of trust
* Revocation key
The problem is that, as Einstein said:
Everything should be made as simple as possible, but no simple.
Same problem I can't talk bitcoin with most of my real-life friends. They are incredibly smart people, but they are not familiar with key concepts about BTC and don't wanna wrap their minds around it when we're hanging out having fun.