The maths is backwards. To take an example, if I submit two stories under a log2-scaled points system which get four upvotes, then if you submit a single story, that story needs to get 16 upvotes for you to match my karma.

Assuming that people are chasing karma (let's leave why to the side for a second, because I don't understand it either), then it's far more efficient to submit lots of low-scoring stories than to even bother thinking about high-scoring ones.