There's a big intrinsic reward for claiming to find something completely new that contradicts all established wisdom. Seminars sell better when they claim to reveal "secrets" or "all-new, all different" results. I admit that I always hope for new findings in our own research, because I know that they'd make us more money. But year after year, the usability findings remain fairly robust and steady, and I'd rather report the truth than increase revenue. Luckily, there are enough honorable usability experts in the world that the findings of most other reports are similar to our own.