>I start to wonder if the "difficulty" in email encryption is actually people just being lazy

I think it's a combination of this and perhaps some ignorance as to the implications of skipping these processes, hence they aren't taken seriously. I'm not sure if more education on this is the solution or not, since it seems a lot of people don't really care about these internals and don't want to take the time to understand what's going on. I'm not sure I'd describe this as laziness or just stubbornness.

Users tend to be very goal-oriented and with (for example) TLS certificate validation errors, these simply stand in the way of what the end-user is trying to achieve. There have been a couple of studies done on how users tend to just dismiss these errors http://static.usenix.org/legacy/events/sec09/tech/full_paper...