I can't speak from experience in RE, but this very much describes me.
I think the boredom sets in after reaching a level of mastery, and experts say 10,000 hours before you really master something. This isn't really a problem as you can delegate these tasks keeping half a watchful eye and only stepping in when you notice things abnormal (with your experience you can spot it quickly), and learn a related subject.
The problem is too many diversions to your attention, spreading yourself too thin, and jumping to something new and interesting before really mastering the last. In my hobbies I never got bored of what I was doing, just something else captured my attention and things got left behind. I mean jumping to something completely not related, not a different aspect of the same area. (my "hobbies" have varied from cars, computers, home audio, car audio, electronics, computer programming, photography, motorcycles, hiking, bicycling, running, on and on the list goes) I'd say I never mastered any of them and I still find most interesting, I just don't do them anymore for various reasons.
I have stuck with the same area of work for 10 years now, but now I am truly bored with it. I could move to another related subject, but I never intended for this to be my lifelong field and want to move on. Luckily I'm young (29), am financially able to start anew and have the GI Bill still so this is a good option for me.
Real estate/business seems varied enough to hold my attention as an area of study, but I wholly expect my focus to wander to different aspects over time and I'm ok with that. I just need to be mindful to avoid dabbling in too many aspects at once...