> But why does he need students to do his own research? That's a phenomenally good question. Short answer: because of incentives in academia(). To be high up

> But why does he need students to do his own research? That's a phenomenally good question. Short answer: because of incentives in academia(). To be high up in the academic hierarchy(), you want top-ranked publications. So you work on those and score a few - good on you! However, a researcher in the same field outdid you by publishing their own work AND supervising a student. That increased their output, so they get the promotion. Now they get more means to attract phd students and postdocs, all collaborating with them, further increasing output. The nasty thing is that this cycle has knock-on effects. Do everything by yourself and you're stagnating; collaborate and you are rewarded with more recognition, promotion, more citations, more reviewer invitations, more invites to give talks/keynotes, etc. And: more quantity and quality in those trigger more and higher-valued of those. Suddenly you're growing into a "respected member of the community" - which strengthens your position at your instituting. Stronger position locally is more local options for growth, leading to the next cycle. TL;DR: Because the direction of academia is in the hands of managers (uni admins, politicians, grant body admins), and managers need quantifiable data... so you're incentiviced to make your numbers go up.