Marshall,
Before they started using sealed bearings I was routinely getting at least 100,000 miles from the original wheel bearings on my Toyota pickups. And I was not repacking them..didn't know any better in those days. I'd drive them until they disintegrated.
That is true about the sideways loads during tight maneuvers, but 5 or 10 thousand intervals for repack still seems more often than necessary to me. I'll check them again at around 20,000 miles unless they give me a reason to do it sooner.
Dean