You are not taking the efficiency argument far enough: if the market is efficient, it isn't a good use of time to do your research. But if it's not worth anyone

You are not taking the efficiency argument far enough: if the market is efficient, it isn't a good use of time to do your research. But if it's not worth anyone's time to do research, the market will no longer be efficient. The market may be 'efficient' in the sense that people inclined to do research have a fair tradeoff between time spent researching and the benefits thereof. But it is incoherent for the markets to be perfectly efficient, in the sense that investors are able to rationally appraise the value of every single stock, but are fully incapable of appraising the value of their own time.