I’m not so sure. Many other "household names" on askscience seem to be highly upvoted, apparently without shenanigans (but who knows?!) Even I have several 1000+ karma answers there, and many more 100+ ones and I’m a nobody. There’s also simply not that much competition on askscience! If you’re consistently able to write good, a-few-paragraph answers to questions in a particular field, and are also available for discussion and followup questions, it’s not that difficult to become commonly recognized and reap a lot of karma there without having to compete against others.